RT Journal Article SR Electronic T1 Biomarkers of exposure to low concentrations of benzene: a field assessment. JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 68 OP 68 DO 10.1136/oem.54.1.68 VO 54 IS 1 A1 E S Johnson YR 1997 UL http://oem.bmj.com/content/54/1/68.1.abstract AB