Cita APA (7th ed.)

Grabau, A. W., & Shimer, H. W. (1910). North american index fossils. Invertebrates. A. G. Seiler.

Cita Chicago (17th ed.)

Grabau, Amadeus W., i Hervey Woodburn Shimer. North American Index Fossils. Invertebrates. Nueva York: A. G. Seiler, 1910.

Cita MLA (9th ed.)

Grabau, Amadeus W., i Hervey Woodburn Shimer. North American Index Fossils. Invertebrates. A. G. Seiler, 1910.