APA (7th ed.) Citation

Christensen, C. (1928). On the systematic position of Polypodium vulgare.

Chicago Style (17th ed.) Citation

Christensen, Carl. On the Systematic Position of Polypodium Vulgare. København, 1928.

MLA (9th ed.) Citation

Christensen, Carl. On the Systematic Position of Polypodium Vulgare. 1928.

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