1. Hamblin, P. Environmentally Compatible Lubricants: Trends, Standards and Terms. Proc. Environmental Aspects in Production and Utilization of Lubricants. Sopron, Sept. 13–15, 1995.
2. Randles, S.J. Formulation of Environmentally Acceptable Lubricants. 49th STLE Annual Meeting, May 1–5, 1994, Pittsburgh
3. Steber, J. Native Esters: Base Oils for High Performance and Environmentally Acceptable Hydraulic Fluids. Part B: Ecological Aspects (in German) Proc. 8th International Colloquium `Tribology 2000', Jan. 1992 TAE, Ostfildern
4. Bartz, W.J. Biologically Fast Degradable Lubricants and Operational Fluids (in German), TAE-Course Tribologie und Schmierungstechnik.
5. Schmoltzi, M. Framework of Laws and Economic Aspects of Rape Seed Oils as Lubricants (in German). In: Biologically Fast Degradable Lubricants and Operational Fluids. W.J. Bartz, Ehningen, expert-verlag 1993.