@article{AFM_2015_40_1_a28,
     author = {Hayk Mikayelyan and Henrik Shahgholian},
     title = {Hopf's lemma for a class of singular/degenerate {PDE-s}},
     journal = {Annales Fennici Mathematici},
     pages = {475--484},
     publisher = {mathdoc},
     volume = {40},
     number = {1},
     year = {2015},
     doi = {10.5186/aasfm.2015.4033},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.2015.4033/}
}