APA (7th ed.) Citation

Friedl, H., & Luhr, O. (2009). Manufacturing Cost Data on Artificial Ice. Project Gutenberg.

Chicago Style (17th ed.) Citation

Friedl, Herman, and Otto Luhr. Manufacturing Cost Data on Artificial Ice. Project Gutenberg, 2009.

MLA (9th ed.) Citation

Friedl, Herman, and Otto Luhr. Manufacturing Cost Data on Artificial Ice. Project Gutenberg, 2009.

Warning: These citations may not always be 100% accurate.