Dyfyniad APA

Cobban, W., & Kennedy, W. (1990). Observations on the Cenomanian (Upper Cretaceous) ammonite Calycoceras (Calycoceras) obrieni Young, 1957 from Arizona and New Mexico.

Dyfyniad Arddull Chicago

Cobban, W., and W. Kennedy. Observations on the Cenomanian (Upper Cretaceous) Ammonite Calycoceras (Calycoceras) Obrieni Young, 1957 from Arizona and New Mexico. 1990.

Dyfyniad MLA

Cobban, W., and W. Kennedy. Observations on the Cenomanian (Upper Cretaceous) Ammonite Calycoceras (Calycoceras) Obrieni Young, 1957 from Arizona and New Mexico. 1990.

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