RT Journal Article SR Electronic T1 Trail degradation as influenced by environmental factors: A state-of-the-knowledge review JF Journal of Soil and Water Conservation FD Soil and Water Conservation Society SP 130 OP 136 VO 51 IS 2 A1 Yu-Fai Leung A1 Jeffrey L. Marion YR 1996 UL http://www.jswconline.org/content/51/2/130.abstract AB