Ivantsov, A. Yu (2010-12-01). "Paleontological evidence for the supposed precambrian occurrence of mollusks". Paleontological Journal (dalam bahasa Inggris). 44 (12): 1552–1559. doi:10.1134/S0031030110120105. ISSN1555-6174.
Ivantsov, A. Yu (2010-12-01). "Paleontological evidence for the supposed precambrian occurrence of mollusks". Paleontological Journal (dalam bahasa Inggris). 44 (12): 1552–1559. doi:10.1134/S0031030110120105. ISSN1555-6174.