NewCROP has Proso Millet information at: Foxtail and Proso Millet—D.D. Baltensperger
Millets: Alternative Field Crops Manual, University of Wisconson Cooperative Extension Service, University of Minnesota Extension Service, Center for Alternative Plant & Animal Products
New Crops for Canadian Agriculture—Ernest Small
Magness J.R. et al. 1971. Food and feed crops of the United States.
And outside links to more Proso Millet info:
Panic grasses from Lost Crops of Africa: Volume I: Grains
Ecofarming: No-till Ecofallow Proso Millet in Winter Wheat Stubble. From the University of Nebraska.
Millet Production Guide by: R. D. Baker, Extension Agronomist, New Mexico State University.