Bernard Wood: Michael Herbert Day (1927–2018). In: American Journal of Physical Anthropology. Band 167, Nr. 4, 2018, S. 697–700, doi:10.1002/ajpa.23693.
M. H. Day und John Russell Napier: Hominid fossils from Bed 1, Olduvai Gorge, Tanganyika: Fossil Foot Bones. In: Nature. Band 201, Nr. 4923, 1964, S. 969–970, doi:10.1038/201969a0.
M. H. Day und Ernie H. Wickens: Laetoli Pliocene hominid footprints and bipedalism. In: Nature. Band 286, Nr. 5771, 1980, S. 385–387, doi:10.1038/286385a0.
M. H. Day: Early Homo sapiens Remains from the Omo River Region of South-west Ethiopia: Omo Human Skeletal Remains. In: Nature. Band 222, Nr. 5199, 1969, S. 1135–1138, doi:10.1038/2221135a0.
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M. H. Day und Chris Stringer: The Omo Kibish cranial remains and classification within the genus Homo. In: L'Anthropologie. Band 95, Nr. 2–3, 1991, S. 573–594, Zusammenfassung.