References
- Cotta Ramusino, M., Pacchetti, G. & Lucchese, A., 1981: Influence of Chromium (VI) upon Stream Ephemeroptera in the Pre-Alps. — Bull. Environm. Contam. Toxicol. 26: 228–232.
- I.R.S.A. (Istituto di Ricerca sulle Acque — Water Research Institute), 1972: Methods for Water Analysis. — Publ. La Pergamena, Roma (in Italian).
- Nie, N. H., Hull, C. H., Jenkins, J. G., Steinbrenner, K. & Bent, D. H., 1979: Statistical Package for the Social Sciences. — McGraw-Hill.