References

1. Yabe, N. (2013), Environmental and economic evaluations of centralized biogas plants running on cow manure in Hokkaido, Japan, Biomass and Bioenergy, 49, 143-151, doi:10.1016/j.biombioe.2012.12.001.
2. Saving Philippine reefs, Summary field report: Coral reef surveys for conservation in southwest Bohol, The Sulu Fund for Marine Conservation Foundation, Inc., June 1999.