APA-referens (7:e uppl.)

Humbert, F. L. (1968). Selection and wear of pebbles on gravel beaches.

Chicago-referens (17:e uppl.)

Humbert, Fekko Lucas. Selection and Wear of Pebbles on Gravel Beaches. [Groningen, 1968.

MLA-referens (8:e uppl.)

Humbert, Fekko Lucas. Selection and Wear of Pebbles on Gravel Beaches. 1968.