Dyfyniad APA

(1987). The New Encyclopaedia Britannica Volume 19 [Excretion and excretory system]. The University of Chicago.

Dyfyniad Arddull Chicago

The New Encyclopaedia Britannica Volume 19 [Excretion and Excretory System]. The University of Chicago, 1987.

Dyfyniad MLA

The New Encyclopaedia Britannica Volume 19 [Excretion and Excretory System]. The University of Chicago, 1987.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.