Cita APA (7th ed.)

Spoel, S. v. d. (1976). Pseudothecosomata, Gymnosomata and Heteropoda (Gastropoda). Bohn, Scheltema & Holkema.

Cita Chicago (17th ed.)

Spoel, S. van der. Pseudothecosomata, Gymnosomata and Heteropoda (Gastropoda). Amsterdam: Bohn, Scheltema & Holkema, 1976.

Cita MLA (9th ed.)

Spoel, S. van der. Pseudothecosomata, Gymnosomata and Heteropoda (Gastropoda). Bohn, Scheltema & Holkema, 1976.