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I was a co-author on the following publications (titles link where possible to pre/post-prints, which are free to download, since otherwise subscriptions may be required).

See also my Google Scholar page, my ORCID page, my arXiv page and my inSPIRE page.

Selected publications

(A full list of publications follows below)

• T. Brown, J. Hampp, Ultra-long-duration energy storage anywhere: Methanol with carbon cycling, Joule, 2023, doi:10.1016/j.joule.2023.10.001
  
  What does a renewable power system look like that is reliable whatever the weather? We make the case for e-methanol with carbon cycling. Combust methanol in pure oxygen in an Allam cycle turbine; this allows easy capture of high-pressure, pure CO2; then cycle CO2 back for more methanol synthesis with green hydrogen. Advantage versus hydrogen storage: methanol can be stored anywhere in aboveground tanks, whereas hydrogen needs salt deposits for cost-effective storage in underground caverns, which are not available in large parts of the world.

• F. Neumann, E. Zeyen, M. Victoria, T. Brown, The Potential Role of a Hydrogen Network in Europe, Joule, 2023, postprint arXiv:2207.05816, doi:10.1016/j.joule.2023.06.016
  
  Would a hydrogen pipeline network help Europe to reach its targets to reduce carbon dioxide emissions? How does it compare to power grid expansion? We explore these issues in a high-resolution sector-coupled model of the European energy system. We find that developing a hydrogen network reduces system costs by up to 26 billion Euros per year (3.4%), with the highest benefits when electricity grid reinforcements cannot be realised. Between 64% and 69% of this network could be built from repurposed natural gas pipelines.

• J. Hampp, M. Düren, Tom Brown, Import options for chemical energy carriers from renewable sources to Germany, PLOS ONE, 2023, open access, postprint arXiv:2107.01092, doi:10.1371/journal.pone.0281380, code on GitHub
  
  We compared the costs for importing green hydrogen and derivatives like ammonia, methanol and hydrocarbons to Germany up to 2050. Where hydrogen itself is needed, pipeline imports from Europe and neighbouring regions are lowest cost. For easier-to-transport derivative fuels, the best renewable resources worldwide, such as those in South America, can be used.

• M. Victoria, E. Zeyen, T. Brown, Speed of technological transformations required for distinct climate ambitions in Europe, Joule, 2022, preprint arXiv:2109.09563, doi:10.1016/j.joule.2022.04.016, code on GitHub
  
  In a model of the transformation of all energy and feedstock demand in Europe for the period 2020-50, we consider how stricter carbon budgets affect the timing of when critical technologies appear. Stricter targets require a fast ramp up of water electrolysis, carbon capture and hydrogen networks before 2035.

• T. Brown, D. Schlachtberger, A. Kies, S. Schramm, M. Greiner, Synergies of sector coupling and transmission reinforcement in a cost-optimised, highly renewable European energy system, Energy, 2018, postprint arXiv:1801.05290, all input data, code and output data on Zenodo, doi:10.1016/j.energy.2018.06.222
  
  We combined sector coupling, most often seen in studies for single regions, with a pan-European grid model. We showed that the flexibility from battery electric vehicles (BEV) pairs well with the daily variations of solar, while power-to-gas units (P2G) and long-term thermal energy storage (LTES) balance the synoptic and seasonal variations of demand and renewables. In all scenarios, an expansion of cross-border transmission reduces system costs, but the more tightly the energy sectors are coupled, the weaker the benefit of transmission reinforcement becomes.

• T. Brown, T. Bischof-Niemz, K. Blok, C. Breyer, H. Lund, B.V. Mathiesen, Response to 'Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems', Renewable and Sustainable Energy Reviews, May 2018, open access, postprint arXiv:1709.05716, doi:10.1016/j.rser.2018.04.113
  
  Several myths surround 100% renewable energy systems purporting that they are not feasible, too complicated or too expensive. In this paper we demonstrated how 100% renewable systems are not just feasible, but economically viable too. We provided a comprehensive review of the wide literature on the topic and addressed each of the points critics have directed at highly-renewable energy modelling, including topics such as demand projections, temporal resolution, extreme events, ancillary services, grid reinforcement, fuel sources and technological readiness.

• T. Brown, J. Hörsch, D. Schlachtberger, PyPSA: Python for Power System Analysis, Journal of Open Research Software, 6(1), 2018, open access, postprint arXiv:1707.09913, doi:10.5334/jors.188, code on GitHub
  
  Python for Power System Analysis (PyPSA) is a widely-used free software toolbox that we developed to simulate and optimise modern energy systems over multiple periods. PyPSA includes models for conventional generators with unit commitment, variable wind and solar generation, storage units, coupling to other energy sectors, and mixed alternating and direct current networks. It can perform load flow calculations, linear optimal power flow and total energy system least-cost multi-period optimisation of investment and operation. It is designed to be easily extensible and to scale well with large networks and long time series.

All publications

• P. Glaum, F. Neumann, T. Brown, Offshore power and hydrogen networks for Europe's North Sea, 2024, preprint arXiv:2404.09721

• F. Neumann, J. Hampp, T. Brown, Energy Imports and Infrastructure in a Carbon-Neutral European Energy System, 2024, preprint arXiv:2404.03927

• I. Riepin, T. Brown, V. Zavala, Spatio-temporal load shifting for truly clean computing, 2024, preprint on Zenodo

• E. Zeyen, I. Riepin, T. Brown, Temporal regulation of renewable supply for electrolytic hydrogen, 2024, doi:10.1088/1748-9326/ad2239

• I. Riepin, T. Brown On the means, costs, and system-level impacts of 24/7 carbon-free energy procurement, 2024, preprint arXiv:2403.07876

• T. Brown, J. Hampp, Ultra-long-duration energy storage anywhere: Methanol with carbon cycling, Joule, 2023, doi:10.1016/j.joule.2023.10.001

• F. Hofmann, C. Tries, F. Neumann, E. Zeyen, T. Brown, H2 and CO2 Network Strategies for the European Energy System, 2024, preprint arXiv:2402.19042

• C. Tries, F. Hofmann, T. Brown, Benefits from Islanding Green Hydrogen Production, 2023, preprint arXiv:2310.12606

• F. Neumann, E. Zeyen, M. Victoria, T. Brown, The Potential Role of a Hydrogen Network in Europe, Joule, 2023, postprint arXiv:2207.05816, doi:10.1016/j.joule.2023.06.016

• I. Riepin, T. Brown, The value of space-time load-shifting flexibility for 24/7 carbon-free electricity procurement, 2023, doi:10.5281/zenodo.8185849

• F. Mockert, C.M. Grams, T. Brown, F. Neumann, Meteorological conditions during Dunkelflauten in Germany: Characteristics, the role of weather regimes and impacts on demand, Meteorological Applications, 2023, preprint arXiv:2212.04870, doi:10.1002/met.2141

• M. Frysztacki, V. Hagenmeyer, T. Brown, Inverse methods: How feasible are spatially low-resolved capacity expansion modeling results when disaggregated at high resolution?, Energy, 2023, preprint arXiv:2209.02364, doi:10.1016/j.energy.2023.128133

• E. Zeyen, M. Victoria, T. Brown, Endogenous learning for green hydrogen in a sector-coupled energy model for Europe, Nature Communications, 2023, postprint arXiv:2205.11901, doi:10.1038/s41467-023-39397-2

• F. Neumann, T. Brown, Broad Ranges of Investment Configurations for Renewable Power Systems, Robust to Cost Uncertainty and Near-Optimality, iScience, 2023, open access, preprint arXiv:2111.14443, doi:10.1016/j.isci.2023.106702

• P. Glaum, F. Neumann, T. Brown, Offshore Wind Integration in the North Sea: The Benefits of an Offshore Grid and Floating Wind, accepted to International Conference on the European Energy Market (EEM), 2023, preprint arXiv:2305.01996

• J. Hampp, M. Düren, Tom Brown, Import options for chemical energy carriers from renewable sources to Germany, PLOS ONE, 2023, open access, postprint arXiv:2107.01092, doi:10.1371/journal.pone.0281380, code on GitHub

• E. Zeyen, I. Riepin, T. Brown, Hourly versus annually matched renewable supply for electrolytic hydrogen, 2022, doi:10.5281/zenodo.7457440

• I. Riepin, T. Brown, System-level impacts of 24/7 carbon-free electricity procurement in Europe, 2022, doi:10.5281/zenodo.7180097

• M. Millinger, L. Reichenberg, F. Hedenus, G. Berndes, E. Zeyen, T. Brown, Are biofuel mandates cost-effective? - an analysis of transport fuels and biomass usage to achieve emissions targets in the European energy system, Applied Energy, 2022, preprint arXiv:2207.03000, doi:10.1016/j.apenergy.2022.120016

• M. Victoria, E. Zeyen, T. Brown, Speed of technological transformations required for distinct climate ambitions in Europe, Joule, 2022, preprint arXiv:2109.09563, doi:10.1016/j.joule.2022.04.016

• M. Frysztacki, G. Recht, T. Brown, A comparison of clustering methods for the spatial reduction of renewable electricity optimisation models of Europe, Energy Informatics, 2022, doi:10.1186/s42162-022-00187-7

• F. Neumann, V. Hagenmeyer, T. Brown, Assessments of linear power flow and transmission loss approximations in coordinated capacity expansion problems, Applied Energy, 2022, preprint arXiv:2008.11510, doi:10.1016/j.apenergy.2022.118859

• A. Shokri Gazafroudi, E. Zeyen, M. Frysztacki, F. Neumann, T. Brown, Long-Term Benefits for Renewables Integration of Network Boosters for Corrective Grid Security, 2021, preprint arXiv:2112.06667

• F. Hofmann, J. Hampp, F. Neumann, T. Brown, J. Hörsch, atlite: A Lightweight Python Package for Calculating Renewable Power Potentials and Time Series, Journal of Open Source Software, 2021, doi:10.21105/joss.03294

• T. Brown, L. Reichenberg, Decreasing market value of variable renewables can be avoided by policy action, Energy Economics, 2021, postprint arXiv:2002.05209, doi:10.1016/j.eneco.2021.105354

• E. Zeyen, V. Hagenmeyer, T. Brown, Mitigating heat demand peaks in buildings in a highly renewable European energy system, Energy, 2021, postprint arXiv:2012.01831, doi:10.1016/j.energy.2021.120784

• M. Frysztacki, J. Hörsch, V. Hagenmeyer, T. Brown, The strong effect of network resolution on electricity system models with high shares of wind and solar, Applied Energy, 2021, preprint arXiv:2101.10859, doi:10.1016/j.apenergy.2021.116726

• A. Shokri Gazafroudi, F. Neumann, T. Brown, Topology-based approximations for N-1 contingency constraints in power transmission networks, International Journal of Electrical Power & Energy Systems, 2021, postprint arXiv:2211.00970, doi:10.1016/j.ijepes.2021.107702

• M. Victoria, K. Zhu, T. Brown, G.B. Andresen, M. Greiner, Early decarbonisation of the European energy system pays off, Nature Communications, 2020, preprint arXiv:2004.11009, doi:10.1038/s41467-020-20015-4

• M. Frysztacki, T. Brown, Modeling Curtailment in Germany: How Spatial Resolution Impacts Line Congestion, accepted to the 17th International Conference on the European Energy Market, 2020, preprint arXiv:2009.03801, doi:10.1109/EEM49802.2020.9221886

• F. Neumann, T. Brown, Transmission Expansion Planning Using Cycle Flows, accepted to ACM e-Energy 2020, preprint arXiv:2004.08702, doi:10.1145/3396851.3397688

• T. Brown, D. Schlachtberger, A. Kies, S. Schramm, M. Greiner, Synergies of sector coupling and transmission reinforcement in a cost-optimised, highly renewable European energy system, Energy, 2018, postprint arXiv:1801.05290, all input data, code and output data on Zenodo, doi:10.1016/j.energy.2018.06.222

• T. Brown, T. Bischof-Niemz, K. Blok, C. Breyer, H. Lund, B.V. Mathiesen, Response to 'Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems', Renewable and Sustainable Energy Reviews, May 2018, open access, postprint arXiv:1709.05716, doi:10.1016/j.rser.2018.04.113

• A. Orths, C.L. Anderson, T. Brown, J. Mulhern, D. Pudjianto, B. Ernst, M. O'Malley, J. McCalley, G. Strbac, Flexibility From Energy Systems Integration: Supporting Synergies Among Sectors, IEEE Power & Energy Magazine, November 2019, doi:10.1109/MPE.2019.2931054

• M. Victoria, K. Zhu, T. Brown, G.B. Andresen, M. Greiner, The role of photovoltaics in a sustainable European energy system under variable CO2 emissions targets, transmission capacities, and costs assumptions, Progress in Photovoltaics, 2019, postprint arXiv:1911.06629, doi:10.1002/pip.3198

• F. Neumann, T. Brown, The Near-Optimal Feasible Space of a Renewable Power System Model, Electric Power Systems Research, 2020, postprint arXiv:1910.01891, doi:10.1016/j.epsr.2020.106690

• M. Victoria, K. Zhu, T. Brown, G.B. Andresen, M. Greiner, The role of storage technologies throughout the decarbonisation of the sector-coupled European energy system, Energy Conversion and Management, 2019, postprint arXiv:1906.06936 doi:10.1016/j.enconman.2019.111977

• T. Brown, M. Schäfer, M. Greiner, Sectoral Interactions as Carbon Dioxide Emissions Approach Zero in a Highly-Renewable European Energy System, Energies, 2019, doi:10.3390/en12061032

• F. Neumann, T. Brown, Heuristics for Transmission Expansion Planning in Low-Carbon Energy System Models, accepted to the 16th International Conference on the European Energy Market, 2019, preprint arXiv:1907.10548, doi:10.1109/EEM.2019.8916411

• H. Liu, G.B. Andresen, T. Brown, M. Greiner, A high-resolution hydro power time-series model for energy systems analysis: Validated with Chinese hydro reservoirs, MethodsX, 2019, doi:10.1016/j.mex.2019.05.024

• H. Liu, G.B. Andresen, T. Brown, M. Greiner, The role of hydro power, storage and transmission in the decarbonization of the Chinese power system, Applied Energy, 2019, postprint arxiv:1810.10347 doi:10.1016/j.apenergy.2019.02.009

• K. Zhu, M. Victoria, T. Brown, G.B. Andresen, M. Greiner, Impact of CO2 prices on the design of a highly decarbonised coupled electricity and heating system in Europe, Applied Energy, 2018, postprint arXiv:1809.10369, doi:10.1016/j.apenergy.2018.12.016

• D. Schlachtberger, T. Brown, M. Schäfer, S. Schramm, M. Greiner, Cost optimal scenarios of a future highly renewable European electricity system: Exploring the influence of weather data, cost parameters and policy constraints, Energy, 2018, postprint arXiv:1803.09711, doi:10.1016/j.energy.2018.08.070

• J. Hörsch, F. Hofmann, D. Schlachtberger and T. Brown, PyPSA-Eur: An Open Optimisation Model of the European Transmission System, Energy Strategy Reviews, 2018, preprint arXiv:1806.01613, doi:10.1016/j.esr.2018.08.012

• M. Schlott, A. Kies, T. Brown, S. Schramm, M. Greiner, The Impact of Climate Change on a Cost-Optimal Highly Renewable European Electricity Network, Applied Energy, 2018, postprint arXiv:1805.11673, doi:10.1016/j.apenergy.2018.09.084

• F. Hofmann, M. Schäfer, T. Brown, J. Hörsch, M. Greiner, S. Schramm, Principal flow patterns across renewable electricity networks, Europhysics Letters, 2018, postprint arXiv:1807.07771, doi:10.1209/0295-5075/124/18005

• J. Weber, H. Heinrichs, B. Gillessen, T. Brown, J. Hörsch, D. Maybe, D. Witthaut, Counter-intuitive behaviour of energy system models under CO2 caps and prices, Energy, 2018, preprint arxiv:1809.03157, doi:10.1016/j.energy.2018.12.052

• B. Tranberg, M. Schäfer, T. Brown, J. Hörsch, M. Greiner, Flow-based analysis of storage usage in a low-carbon European electricity scenario, 15th International Conference on the European Energy Market - EEM 2018, 2018, preprint arXiv:1806.02549

• T. Brown, J. Hörsch, D. Schlachtberger, PyPSA: Python for Power System Analysis, Journal of Open Research Software, 6(1), 2018, open access, postprint arXiv:1707.09913, doi:10.5334/jors.188

• S. Pfenninger, L. Hirth, I. Schlecht, E. Schmid, F. Wiese, T. Brown, C. Davis, B. Fais, M. Gidden, H.Heinrichs, C. Heuberger, S. Hilpert, U. Krien, C. Matke, A. Nebel, R. Morrison, B. Müller, G. Pleßmann, M. Reeg, J. C. Richstein, A. Shivakumar, I. Staffell, T. Tröndle, C. Wingenbach, Opening the black box of energy modelling: strategies and lessons learned, Energy Strategy Reviews, 2017, open access, postprint arXiv:1707.08164, doi:10.1016/j.esr.2017.12.002

• J. Hörsch, T. Brown, The role of spatial scale in joint optimisations of generation and transmission for European highly renewable scenarios, 14th International Conference on the European Energy Market - EEM 2017, 2017, preprint arXiv:1705.07617, doi:10.1109/EEM.2017.7982024

• D. Schlachtberger, T. Brown, S. Schramm, M. Greiner, The Benefits of Cooperation in a Highly Renewable European Electricity Network, Energy, 134, 469-481, 2017, postprint arXiv:1704.05492, all input data, code and output data on Zenodo, doi:10.1016/j.energy.2017.06.004

• J. Hörsch, H. Ronellenfitsch, D. Witthaut, T. Brown, Linear Optimal Power Flow Using Cycle Flows, Electric Power Systems Research, volume 158, pages 126-135, 2017, preprint arXiv:1704.01881, doi:10.1016/j.epsr.2017.12.034

• E.H. Eriksen, L.J. Schwenk-Nebbe, B. Tranberg, T. Brown, M. Greiner, Optimal heterogeneity in a simplified highly renewable European electricity system, Energy, 133, 913-928, 2017, postprint arXiv:1706.00463, doi:10.1016/j.energy.2017.05.170

• J. Bertsch, T. Brown, S. Hagspiel, L. Just, The relevance of grid expansion under zonal markets, The Energy Journal, Volume 38, Number 5, 2017, EWI Working Paper 15/07, doi:10.5547/01956574.38.5.jber

• H. Ronellenfitsch, D. Manik, J. Hörsch, T. Brown, D. Witthaut, Dual theory of transmission line outages, IEEE Transactions on Power Systems, 2017, postprint arXiv:1606.07276, doi:10.1109/TPWRS.2017.2658022

• Scaling Up Variable Renewable Power: The Role of Grid Codes, 2016, International Renewable Energy Agency

• T. Brown, P. Schierhorn, E. Tröster, T. Ackermann, Optimising the European transmission system for 77% renewable electricity by 2030, IET Renewable Power Generation, Volume 10, Issue 1, 2015, postprint version, doi:10.1049/iet-rpg.2015.0135

• T. Brown, T. Ackermann, N. Martensen, Solar Power Integration on the Seychelles Islands, Field Actions Science Reports Special Issue 15: Decentralized Electrification and Development, 2016

• L. Jiang, C. Wang, Y. Huang, Z. Pei, S. Xin, W. Wang, S. Ma, T. Brown, Growth in Wind and Sun: Integrating Variable Generation in China, IEEE Power and Energy Magazine, Volume 13, Issue 6, 2015, doi:10.1109/MPE.2015.2458754

• Integrating Renewables in Jiangsu Province, China (PDF, 1.2 MB) presented at the 14th International Workshop on Integration of Wind Power into Power Systems in Brussels, 2015

• Greenpeace powE[R] 2020 Integration of Renewables in Jiangsu, China (in Chinese), published July 2015, Beijing, English press release

• T. Brown, Transmission Network Loading in Europe with High Shares of Renewables, IET Renewable Power Generation, Volume 9, Issue 1, 2015, postprint version, https://doi.org/10.1049/iet-rpg.2014.0114

• S. Hagspiel, C. Jägemann, D. Lindenberger, T. Brown, S. Cherevatskiy, E. Tröster, Cost-Optimal Power System Extension under Flow-Based Market Coupling (subscription required, part of the Smooth PV project) in Energy, 66, pp. 654-666, 2014, free to download: EWI Working Paper 13/09, preprint version, doi:10.1016/j.energy.2014.01.025

• Optimising the European Transmission System for 77% Renewables by 2030 (PDF, 1.8 MB) presented at the 13th International Workshop on Integration of Wind Power into Power Systems in Berlin, 2014

• Cycling Requirements for Conventional Power Plants at High Shares of Renewable Energy (PDF, 0.6 MB) presented at the 13th International Workshop on Integration of Wind Power into Power Systems in Berlin, 2014

• The Solar Power Absorption Capacity of the Seychelles Island Systems (PDF, 0.9 MB) presented at the 4th International Workshop on Integration of Solar Power into Power Systems in Berlin, 2014

• Wind Power in a 100% Renewables Scenario for Rhineland-Palatinate (PDF, 1.5 MB) presented at the 13th International Workshop on Integration of Wind Power into Power Systems in Berlin, 2014

• Solar Power in a 100% Renewables Scenario for Rhineland-Palatinate (PDF, 0.6 MB) presented at the 4th International Workshop on Integration of Solar Power into Power Systems, Berlin, 2014

• A Multi-Objective Control Strategy for Distribution Networks with Renewables (PDF, 0.8 MB) presented at the 4th International Workshop on Integration of Solar Power into Power Systems, Berlin, 2014

• Greenpeace powE[R] 2030 European report (PDF, 13 MB) for the grid extensions necessary to accommodate 77% renewable electricity in Europe by 2030, 2014

• Entwicklung und Durchführung einer Impactanalyse für den Klimaschutzplan Nordrhein-Westfalen (PDF, 2.5 MB), Düsseldorf, 2014

• Kurzgutachten zur Eigenstromerzeugung in Rheinland-Pfalz, Darmstadt, March 2014

• Distribution network study for Rhineland-Palatinate (PDF, 13 MB, in German) to reach 100% renewable electricity in the German federal state of Rhineland-Palatinate by 2030, summary in English, 2014

• UMEME 24/7: Analysis of the Stability of the Kenyan Power System (PDF, 5.5 MB), Darmstadt, 2014

• Transmission Network Loading in Europe with High Shares of Renewables (PDF, 1.2 MB), presented at the 3rd International Workshop on Integration of Solar Power into Power Systems in London, 2013

• Smooth PV - Smart Modelling of Optimal Integration of High Penetration of Photovoltaics Final Report, 2013

• Transporting Renewables: Systematic Planning for Long-Distance HVDC Lines (PDF, 4 MB, part of the Smooth PV project) presented at EWEA 2013 in Vienna

• Cost-optimal Power System Extension Under Flow-based Market Coupling and High Shares of Photovoltaics (PDF, 0.3 MB), part of the Smooth PV project) presented at the 2nd International Workshop on Integration of Solar Power into Power Systems in Lisbon, 2012

• T. Brown, Complex matrix model duality in Phys. Rev. D 83 085002 (2011) (1009.0674 [hep-th])

• T. Brown, Cut-and-join operators and N=4 super Yang-Mills in JHEP 1005 058 (1002.2099 [hep-th]; code and examples of U(N) to S_N reduction)

• PhD thesis Gauge/Gravity Duality Beyond the Planar Limit, August 2009

• T. Brown, P.J. Heslop and S. Ramgoolam, Diagonal free field matrix correlators, global symmetries and giant gravitons with Paul Heslop and Sanjaye Ramgoolam in JHEP 0904 089 (0806.1911 [hep-th])

• T. Brown, Permutations and the Loop in JHEP 0806 (2008) 008 (0801.2094 [hep-th])

• T. Brown, P.J. Heslop and S. Ramgoolam, Diagonal multi-matrix correlators and BPS operators in N=4 SYM with Paul Heslop and Sanjaye Ramgoolam in JHEP 0802 (2008) 030 (0711.0176 [hep-th])

• T. Brown, Half-BPS SU(N) Correlators in N=4 SYM in JHEP 0807 (2008) 044 (hep-th/0703202)

• T. Brown, R. de Mello Koch, S. Ramgoolam and N. Toumbas, Correlators, probabilities and topologies in N=4 SYM with Robert de Mello Koch, Sanjaye Ramgoolam and Nick Toumbas in JHEP 0703 (2007) 072 (hep-th/0611290)

• T. Brown, R.F. Griffin, Spectroscopic binary orbits from photoelectric radial velocities, Paper 156: HD 187003 with Roger Griffin in The Observatory, Vol. 121, p. 55-60 (2001)