RT Journal Article SR Electronic T1 Our Part in the Environmental Movement JF Arboriculture & Urban Forestry (AUF) FD International Society of Arboriculture SP 1 OP 7 DO 10.48044/jauf.1991.001 VO 17 IS 1 A1 Pirk, Herb YR 1991 UL http://auf.isa-arbor.com/content/17/1/1.abstract AB