Gaya APA

Eastman, N, J., Hellman, L, M. (1961). Williams Obstetrics Edisi 12 . New York: Appleton-Century-Crofts.

Gaya MLA

Eastman, Nicholson, J.., Hellman, Louis, M.. "Williams Obstetrics Edisi 12". New York: Appleton-Century-Crofts, 1961. Text.