RT Journal Article SR Electronic T1 Psychoactive substance use in truck drivers: occupational health and public health JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 1 OP 1 DO 10.1136/oemed-2013-101791 VO 71 IS 1 A1 A J van der Beek YR 2014 UL http://oem.bmj.com/content/71/1/1.abstract AB