Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- Spores produced inside certain bacterial cells as an adaptation to survive environmental stress. The spores are released upon the death of the parental cell.
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- In some bacteria, a resting structure that can survive harsh environmental conditions.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.
- 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.