APA (7th ed.) Citation

Christensen, C. (1973). Index filicum. Otto Koeltz Antiquariat.

Chicago Style (17th ed.) Citation

Christensen, Carl. Index Filicum. Koenigstein: Otto Koeltz Antiquariat, 1973.

MLA (9th ed.) Citation

Christensen, Carl. Index Filicum. Otto Koeltz Antiquariat, 1973.

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