@Article{ MucNic11, author = { Mucci, Domenico and Nicolodi, Lorenzo }, title = { On the elastic energy density of constrained $Q$-tensor models for biaxial nematics }, journal = { Arch. Rational Mech. Anal. }, year = { 2012 }, volume = { 206 }, pages = { 853--884 }, URL = { http://cvgmt.sns.it/paper/1676/ }, note = { cvgmt preprint} }