References
- Keeley, J. E., 1981: Isoetes howellii: a submerged aquatic CAM plant? — Amer. J. Bot. 68: 420–424.
- Keeley, J. E. 1983: Crassulacean acid metabolism in the seasonally submerged aquatic Isoetes howellii. — Oecologia 58: 57–62.
- Keeley, J. E. & Bowes, G., 1982: Gas exchange characteristics of the submerged aquatic Crassulacean Acid Metabolism plant,Isoetes howellii. — Pl. Physiol. 70: 1455–1458.
- Kluge, M. & Ting, I. P., 1978: Crassulacean Acid Metabolism. — Springer-Verlag, Heidelberg.