Biomass Magazine, Jan. 16, 2014.
http://www.biomassmagazine.com/articles/9901/researchers-there-is-more-to-biofuel-production-than-yield

"When it comes to biofuels, corn leads the all-important category of biomass yield. However, focusing solely on yield comes at a high price. In the current issue of the Proceedings for the National Academy of Sciences, Michigan State University researchers show that looking at the big picture allows other biofuel crops, such as native perennial grasses, to score higher as viable alternatives."

The full paper is available at http://www.pnas.org/content/early/2014/01/08/1309492111.abstract.