APA (7th ed.) Citation

Maginnis, C. D. (2006). Pen Drawing An Illustrated Treatise. Project Gutenberg.

Chicago Style (17th ed.) Citation

Maginnis, Charles Donagh. Pen Drawing An Illustrated Treatise. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Maginnis, Charles Donagh. Pen Drawing An Illustrated Treatise. Project Gutenberg, 2006.

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