Guan, Kaomei, et al. “Embryonic Stem Cells in Vitro - Prospects for Cell and Developmental Biology, Embryotoxicology and Cell Therapy”. ALTEX - Alternatives to Animal Experimentation, vol. 16, no. 3, Aug. 1999, pp. 135-41, https://altex.org/index.php/altex/article/view/1451.