Zhou, Z.; Quan, C.; Liu, Y-S (2012). "Tertiary Ginkgo ovulate organs with associated leaves from North Dakota, U.S.A., and their evolutionary significance". International Journal of Plant Sciences. 173 (1): 67–80. doi:10.1086/662651. S2CID86289858.
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Zhou, Z.; Quan, C.; Liu, Y-S (2012). "Tertiary Ginkgo ovulate organs with associated leaves from North Dakota, U.S.A., and their evolutionary significance". International Journal of Plant Sciences. 173 (1): 67–80. doi:10.1086/662651. S2CID86289858.