Scientific papers and Journal articles on the System

Hugo, M.L. 1998: Difficulty Grading of Hiking Trails. Journal for Research in Sport, Physical Education and Recreation.  21(1) : 47-54  (With Kruger,P.E., Jansen van Vuuren,T.B.R. and Hugo,M.L.(jnr).

Hugo, M.L 1999: Energy Equivalent as a measure of the difficulty rating of hiking trails. Tourism  Geographies  1(3):1-15

Hugo, M.L  2000:A Comprehensive Approach towards the Planning, Grading and Auditing of Hiking Trails as Ecotourism Products. Current Issues in Tourism (lead article) 2(2 & 3):124-136

Hugo, M.L 2000. Grading of Trails. Sustainable Tourism. Papers collected from the 98’ International Geographic Union Study group Meeting. Lisbon.  (pp.166-177).

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