1. Alternative for food processors wastewater;Safferman
2. Food and processing residues in California: resource assessment and potential for power generation.;Matteson;Bioresource Technol,2007
3. Market opportunities for biogas recovery systems;EPA
4. VanderHaak Dairy Digester www.harvestcleanenergy.org/conference/HCE7/PDFs/VanderHaak.pdf
5. USDA, An analysis of energy production costs from anaerobic digestion systems on U.S. livestock production facilities. USDA Technical Note No. 1 (2007).