1. Adams, C. R., K. A. Starner, J. K. Miller, J. G. McNally, M. M. Kirk & D. L. Kirk, 1990. Patterns of organellar and nuclear inheritance among progeny of two geographically isolated strains of Volvox carteri. Curr. Genet. 18: 141–153.
2. Al-Hasani, H. & L. Jaenike, 1992. Characterization of the sex-inducer glycoprotein of Volvox carteri f. weismannia. Sex. Plant Reprod. 5: 8–12.
3. Allen, M. A., 1985. The biology of a species complex in Spirogyra. Ph. D. Thesis, Indiana University.
4. Bell, G., 1992. The emergence of gender and the nature of species in eukaryotic microbes. Verh. dt. zool. Ges. 85: 161–175.
5. Bell, R. A. & J. R. Cain, 1983. Sexual reproduction and hybridization in Chlamydomonas smithii and C. reinhardtii (Chlorophyceae, Volvocales ), Phycologia 22: 243–247.