1. Bonsignore, D., Calissano, P., Cartasegna, C.: Un semplice metodo per la determinatione della ?-aminolevulinicodeÏolvatasi mel sangue. Med. d. Lavoro 56, 199?205 (1965)
2. Coulston, F., Goldberg, L., Griffin, T.B., Russel, C.: The effects of continuous exposure to airborne lead. IV: Exposure of men to particulate lead at a level of 3.2 ?g/m3 and 10.9 ?g/m3. Albany-New York: Institute of Experimental Pathology and Toxicology (Report) 1973a
3. Coulston, F., Goldberg, L., Griffin, T. B., Russel, C.: The effects of continuous exposure to airborne lead. II: Exposure of men to particulate lead at a level of 10.9 ?g/m3. Albany-New York: Institute of Experimental Pathology and Toxicology (Report) 1973b
4. Davis, J. R., Andelman, S. L.: Urinary ?-aminolevulinic acid levels in lead poisoning. I. A modified method for the rapid determination of urinary ?-amino-levulinic acid using disposable ion-exchange chromatography columns. Arch. environm. Hlth 15, 53 (1967)
5. Göthe, G. J., öhman, H., Lindstedt, G.: Exposure to airborne lead in city atmosphere. Work-Environm.-Hlth 10, 13 (1973)