The following are documents prepared by volunteer trail managers for use in actual projects we've been involved as the trail developers. Besides our own experience, there were various additional sources which we relied on heavily for some of the content - including IMBA's Trail Solutions guidelines for building sustainable single-track, Black Rock Mountain Bike Association's adopt-a-trail management agreement with Oregon Department of Forestry, and even the "Whistler Trail Standards for Environmental and Technical Trail Features" by Resort of Municipality of Whistler.