APA (7th ed.) Citation

Petrik-Ott, A. J. (1979). The pteridophytes of Kansas, Nebraska, South Dakota and North Dakota, USA. Cramer.

Chicago Style (17th ed.) Citation

Petrik-Ott, Aleta J. The Pteridophytes of Kansas, Nebraska, South Dakota and North Dakota, USA. Vaduz: Cramer, 1979.

MLA (9th ed.) Citation

Petrik-Ott, Aleta J. The Pteridophytes of Kansas, Nebraska, South Dakota and North Dakota, USA. Cramer, 1979.