Chaw, Shu-Miaw; Parkinson, Christopher L.; Cheng, Yuchang; Vincent, Thomas M.; Palmer, Jeffrey D. (2000-04-11). “Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers”. Proc. Natl. Acad. Sci.97 (8): 4086–4091. doi:10.1073/pnas.97.8.4086.。