Janssen, R. E. (1940). Somefossil Plant Types of Illinois: A restudy of the Lesquereux types in the Wothern collection of the Illinois State Museum, augmented by descriptions of new species from Mazon Creek. Univ. of Chicago Libr.
Chicago-Zitierstil (17. Ausg.)Janssen, Raymond E. Somefossil Plant Types of Illinois: A Restudy of the Lesquereux Types in the Wothern Collection of the Illinois State Museum, Augmented by Descriptions of New Species from Mazon Creek. Chicago, Ill: Univ. of Chicago Libr, 1940.
MLA-Zitierstil (9. Ausg.)Janssen, Raymond E. Somefossil Plant Types of Illinois: A Restudy of the Lesquereux Types in the Wothern Collection of the Illinois State Museum, Augmented by Descriptions of New Species from Mazon Creek. Univ. of Chicago Libr, 1940.
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