Pilsbry, H. A. (1893). Preliminary outline of a new classification of the helices. Proceedings of the Academy of Natural Sciences of Philadelphia. 44: 387-400 [14 February 1893], 401-404 [7 February 1893].
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Pilsbry, H. A.
1893
Preliminary outline of a new classification of the helices.
Proceedings of the Academy of Natural Sciences of Philadelphia
44: 387-400 [14 February 1893], 401-404 [7 February 1893]