The fishes of the west coast of Peru and the Titicaca Basin. Bulletin of the United States National Museum, 95, 1–166
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Studies on the head in fishes. Embryological, morphological, and phylogenetical researches. Part I. Development of the skull in sharks and rays. Acta Zoologica(Stockholm), 21(1–3), 51–267
DOI: 10.1111/j.1463-6395.1940.tb00339.x