Sigma Paper No. 4: Management Control in Modern Government Administration: Some Comparative Practices (1996) Sigma Paper No. 23: Preparing Public Administrations for the European Administrative Space (1998) Sigma Paper No. 26: Sustainable Institutions for European Union Membership (1998) Sigma Paper No. 27: European Principles for Public Administration (1999) Sigma Paper No. 31: Improving Policy Instruments through Impact Assessment (2001) Sigma Paper No. 37: Enlargement of the European Union: An Analysis of the Negotiations for Countries of the Western Balkans (2007) Sigma Paper No. 38: Political Advisors and Civil Servants in European Countries (2007) Sigma Paper No. 39: The Role of Ministries in the Policy System: Policy Development, Monitoring and Evaluation (2007) Sigma Paper No. 43: Organising the Central State Administration: Policies & Instruments (2007)