APA

Ochoa C. M., Ugent D. & Frey F. (1990). The potatoes of South America : Bolivia. Cambridge: Cambridge University Press.

Chicago

Ochoa Carlos M, Ugent Donald and Frey Franz. 1990. The potatoes of South America : Bolivia. Cambridge: Cambridge University Press.

Harvard

Ochoa C. M., Ugent D. and Frey F. (1990). The potatoes of South America : Bolivia. Cambridge: Cambridge University Press.

MLA

Ochoa Carlos M, Ugent Donald and Frey Franz. The potatoes of South America : Bolivia. Cambridge: Cambridge University Press. 1990.