RT Journal Article SR Electronic T1 Contract vs. Company Tree Crews JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 96 OP 98 DO 10.48044/jauf.1981.022 VO 7 IS 4 A1 Anton L. Higgins YR 1981 UL http://auf.isa-arbor.com/content/7/4/96.abstract AB