1. H. L. KUSNETZ, Am. Ind. Hyg. Assoc. J., 17 (1956) 1.
2. R. L. ROCK, MESA, Information Report IR-1015 (U.S. D.O.I), 1975.
3. Y. S. MAYYA, P. KOTRAPPA, Ann. Occup. Hyg., 21 (1978) 169.
4. J. BIGU, CANMET, EMR Canada (Ottawa) Division Report MRL 89-36(TR), 1988.
5. J. BIGU, Health Phys., 55 (1988) 525.