APA (7th ed.) Citation

Petrik-Ott, A. J. (1979). The Pteridophytes of Kansas, Nebraska, South Dakota and North Dakota, U.S.A. J. Cramer.

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

Petrik-Ott, Aleta Jo. The Pteridophytes of Kansas, Nebraska, South Dakota and North Dakota, U.S.A. J. Cramer, 1979.