[←196]
http://www.atsdr.cdc.gov/phs/phs.asp?id=79&tid=20, http://www.atsdr.cdc.gov/phs/phs.asp?id=139&tid=26, http://www.atsdr.cdc.gov/phs/phs.asp?id=46&tid=15, http://www.atsdr.cdc.gov/hac/pha/pha.asp?docid=1341&pg=1