APA (7e ed.) Bronvermelding

Lenz, A. C. (1982). Llandoverian graptolites of the northern Canadian Cordillera: Petalograptus, Cephalograptus, Rhaphidograptus, Dimorphogratus, Retiolitidae, and Monograptidae. ROM.

Chicago (17e ed.) Bronvermelding

Lenz, Alfred C. Llandoverian Graptolites of the Northern Canadian Cordillera: Petalograptus, Cephalograptus, Rhaphidograptus, Dimorphogratus, Retiolitidae, and Monograptidae. Toronto: ROM, 1982.

MLA (8e ed.) Bronvermelding

Lenz, Alfred C. Llandoverian Graptolites of the Northern Canadian Cordillera: Petalograptus, Cephalograptus, Rhaphidograptus, Dimorphogratus, Retiolitidae, and Monograptidae. ROM, 1982.