Friis, R. H. (2012). Essentials of environmental health (2nd ed.). Jones & Bartlett learning.
Chicago-čujuhus (17. p.)Friis, Robert H. Essentials of Environmental Health. 2nd ed. Burlington: Jones & Bartlett learning, 2012.
MLA-čujuhus (9. p.)Friis, Robert H. Essentials of Environmental Health. 2nd ed. Jones & Bartlett learning, 2012.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.