APA (7th ed.) Citation

Sell, P., & Yeo, P. (1970). A revision of the North American species of Euphrasia L. (Scrophulariaceae) ([Sonderdr.].).

Chicago Style (17th ed.) Citation

Sell, Peter, and Peter Yeo. A Revision of the North American Species of Euphrasia L. (Scrophulariaceae). [Sonderdr.]. 1970.

MLA (9th ed.) Citation

Sell, Peter, and Peter Yeo. A Revision of the North American Species of Euphrasia L. (Scrophulariaceae). [Sonderdr.]. 1970.

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