Piotrowski, Ralph; R. Andreas Kraemer 1998: Financial Capacity of the Water Sector and Water Prices in Europe – A Comparison. Paper in the Research Project "Interactions between the Management of the Urban Water Cycle and Environmental Technologies in a Sustainable Development Perspective".

Kraemer, R. Andreas; Ralph Piotrowski 1998: Comparison of Water Prices in Europe. Summary Report. A Contribution to the Research Projects: R&D and Water Management Systems, Research Contract ENV4-CT96-0189, European Commission, Directorate-General 12 (Research), Water 21: Toward Sustainable European Water Management, Research Contract ENV4-CT96-0196, European Commission, Directorate-General 12 (Research).

Kahlenborn, Walter; R. Andreas Kraemer 1998: Sustainable Water Management in Germany. Identification of Non-Sustainable Trends, Recommendations for Action. Berlin.

Kraemer, R. Andreas; Walter Kahlenborn 1996: Sustainable Water Management in Germany. An Overview for the International Symposium 'SustainabIe Water Management' Bonn, 8-9 October 1996. Berlin.