MLA

Parkman, Henry P, and Richard W McCallum. Gastroparesis. Bethesda, MD: Humana Press, 2012.

APA

Parkman, H. P, & McCallum, R. W. (2012). Gastroparesis. Bethesda, MD: Humana Press.

Chicago

Parkman, Henry P., and Richard W McCallum. Gastroparesis. Bethesda, MD: Humana Press, 2012.