1. Cathance River Conservation and Farming
http://www.bowdoin.edu/environmental-studies/service-learning/pdf/Cathance_ag_conservation.pdf
2. Unv of Maine Cooperative Extension- This Old Hayfield: A Fact Sheet on Hayfield Renovation; Aug 2008
http://www.umext.maine.edu/onlinepubs/PDFpubs/2491.pdf
3. Farm Business Mgmt- Machinery Cost Estimates: Forage Field Operations; May 2008
4. Potash and Phosphate Institute- Mixed Hay Fields Respond to NPK in Fertilizer and Manure (New England); May 1998
5. Wikipedia- “Sharecropping”