Symmonds, Mathew C.; William E. Hammitt; Virgil L. Quisenberry (2000). "Managing Recreational Trail Environments". Environmental Management. 25 (5): 549–564. doi:10.1007/s002679910043. PMID10742481.
rootsrated.com
https://rootsrated.com Farlow Gap - Mountain Biking: fall line (2nd paragraph) — "The trail becomes loose and rocky, and becomes fall line into a wide-open rock garden..."