Cobban, W., & Kennedy, W. (1990). Observations on the Cenomanian (Upper Cretaceous) ammonite Calycoceras (Calycoceras) obrieni Young, 1957 from Arizona and New Mexico.
Παραπομπή σε μορφή Chicago (17η εκδ.)Cobban, W., και W. Kennedy. Observations on the Cenomanian (Upper Cretaceous) Ammonite Calycoceras (Calycoceras) Obrieni Young, 1957 from Arizona and New Mexico. 1990.
Παραπομπή σε μορφή MLA (9th εκδ.)Cobban, W., και W. Kennedy. Observations on the Cenomanian (Upper Cretaceous) Ammonite Calycoceras (Calycoceras) Obrieni Young, 1957 from Arizona and New Mexico. 1990.
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