Glossary of Plant Systematics (1st ed.) by Simpson (2006)
- An irregularity during meiosis in which homologous chromosomes do not segregate, which may result in the production of gametes that are unreduced, i.e. have two sets of chromosomes.
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- Failure of sister chromatids to separate in meiosis II or mitosis, or failure of homologous chromosomes to separate in meiosis I. Results in aneuploidy.
- Simpson, M. G. 2006. Plant Systematics. -xi + 590 pp. Elsevier Academic Press, Oxford.
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.