Sims, G. (1972). The Sand dollar. Penguin.
Chicago Style (17th ed.) CitationSims, George. The Sand Dollar. Harmonds-worth: Penguin, 1972.
MLA (9th ed.) CitationSims, George. The Sand Dollar. Penguin, 1972.
Advarsel: Disse citationer er muligvist ikke 100% nøjagtige.