References
- Oborn, E. T., 1960: Iron content of selected water and land plants. Chemistry of iron in natural water. — U. S. Geol. Surv., Water Supply Paper 1459-G.
- Shapiro, J., 1966: The relation of humic color to iron in natural waters. — Verh. Internat. Verein. Limnol. 16, 477–484.
- Shapiro, J. 1964: Effect of yellow organic acids on iron and other metals in water. — J. Amer. Water Works Ass'n. 56, 1062–1082.
- Shapiro, J. 1966: On the measurement of ferrous iron in natural waters. — Limnol. Oceanogr. 11, 293–298.
- Shapiro, J. 1967: Iron available to algae: preliminary report on a new approach to its estimation in lake water through use of the “ferrigram”. — In: Proceedings of an IBP Symposium, “Chemical Environment in the Aquatic Habitat“, held in Amsterdam, October, 1966, 219–228.