Cilimburg, A., Monz, C., and Kehoe, S. (2000) Wildland recreation and human waste: A review of problems, practices, and concerns. Environmental Management, 25, 587-598.

Ells, M.D., The Fate of Feces and Fecal Microorganisms in Human Waste in Alpine, Temperate and Arid Environments and The Impact of Disposal Methods on the Surrounding Environment
Professor Environmental Health and Safety Management, College of Allied Health Sciences, Ferris State University, Big Rapids, MI
http://research.nols.edu/humanwaste_Mt.Rainier.html

Lewin, R.A. (1999) Merde: Excursions into Scientific, Cultural and Socio-historical Coprology. Aurum Press Ltd, London.

Meyer, K. (1994) How to Shit in the Woods. (2nd Edition). Ten Speed Press, Berkeley.

Go and shit under a tree
... Who would have thought rude words are ecologically significant? Contrast the negative connotations of "shit" with the positive message conveyed by the term "night soil", the term used for human excreta in China where it is valued as organic fertilizer. The soils of China could not have supported such a vast population for such a long time if they had invented the flush toilet way back when they invented paper.
http://fehps.une.edu.au/F/s/curric/pMetcalfe/DOCS/NatureNotes/Shit.html

Poo Corner
Every day, people on Earth produce over 5 billion kilos (11 billion pounds) of poop.
http://commtechlab.msu.edu/sites/dlc-me/zoo/zapmain.html