Here are various publications from Dr. Geoff Hill:

Composting Toilets Misnomer Composting toilets are a misnomer: Excessive ammonia from urine inhibits microbial activity yet is insufficient in sanitizing the end-product. (2013)
By Geoffrey B. Hill, Susan A. Baldwin, Björn Vinnerås

Solvita Compost Toilet Evaluation of Solvita compost stability and maturity tests for assessment of quality of end-products from mixed latrine style compost toilets. (2013)
By Geoffrey B. Hill, Susan A. Baldwin, Bjorn Vinnerås

Wilderness Waste The Application and Performance of Urine Diversion to Minimize Waste Management Costs Associated with Remote Wilderness Toilets. (2013)
By Geoff Hill and Greg Henry

Vermicomposting toilets Vermicomposting toilets, an alternative to latrine style microbial composting toilets, prove far superior in mass reduction, pathogen destruction, compost quality, and operational cost. (2012)
By Geoffrey B. Hill and Susan A. Baldwin