http://www.nwf.org/How-to-Help/Garden-for-Wildlife/Gardening-Tips/Build-a-Bee-House.aspx
http://www.pollinatorparadise.com/what_is_pollination.htm
http://edis.ifas.ufl.edu/pdffiles/HS/HS39800.pdf
http://blogs.usda.gov/2011/08/04/usda-forest-service-booklet-touts-value-of-native-bees/#more-34655
http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5306468.pdf
0