@Misc{ FusZho15, author = { Fusco, Nicola and Zhong, Xiao }, title = { On the Euler-Lagrange equation of a functional by Pólya and Szegö }, journal = { }, year = { 2015 }, pages = { }, URL = { http://cvgmt.sns.it/paper/2675/ }, note = { cvgmt preprint} }