%0 Journal Article %A Le, Nam Q. %T On optimal Hölder regularity of solutions to the equation Δu + b ⋅ ∇u = 0 in two dimensions %J Comptes Rendus. Mathématique %D 2017 %P 439-446 %V 355 %N 4 %I Elsevier %U http://www.numdam.org/articles/10.1016/j.crma.2017.02.005/ %R 10.1016/j.crma.2017.02.005 %G en %F CRMATH_2017__355_4_439_0