@article{MTA_2020_5_2_a0,
     author = {Emmanuel N. Barron and Robert Jensen},
     title = {Hopf formulas for nonlinear obstacle problems},
     journal = {Minimax theory and its applications},
     year = {2020},
     volume = {5},
     number = {2},
     zbl = {1451.49039},
     url = {http://geodesic.mathdoc.fr/item/MTA_2020_5_2_a0/}
}