APA aipamena

Abadilla, D. C. (1976). Comfrey: Nature's health food. s.n.].

Chicago Style aipamena

Abadilla, Domingo C. Comfrey: Nature's Health Food. [S.l: s.n.], 1976.

MLA aipamena

Abadilla, Domingo C. Comfrey: Nature's Health Food. s.n.], 1976.