APA (7th ed.) Citation

Oelert, G., Auer, F., & Pertz, K. (1987). Economic issues of renewable energy systems: A guide to project planning. GTZ.

Chicago Style (17th ed.) Citation

Oelert, Gerhard, Falk Auer, and Klaus Pertz. Economic Issues of Renewable Energy Systems: A Guide to Project Planning. Eschborn: GTZ, 1987.

MLA (9th ed.) Citation

Oelert, Gerhard, et al. Economic Issues of Renewable Energy Systems: A Guide to Project Planning. GTZ, 1987.