@article{10_1090_S0894_0347_2011_00702_9,
     author = {Avila, Artur},
     title = {Density of positive {Lyapunov} exponents for {\dh}‘†{\dh}{\textquestiondown}(2,\^a„)-cocycles},
     journal = {Journal of the American Mathematical Society},
     pages = {999--1014},
     publisher = {mathdoc},
     volume = {24},
     number = {4},
     year = {2011},
     doi = {10.1090/S0894-0347-2011-00702-9},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-2011-00702-9/}
}