@article{MOMA_1990__109_2_178463,
     author = {Jianmin Gao},
     title = {A {THeorem} of {Global} {Existence} of {Solutions} to {Nonlinear} {Wave} {Equations} in {Four} {Space} {Dimensions.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {123--134},
     publisher = {mathdoc},
     volume = {109},
     number = {2},
     year = {1990},
     zbl = {0718.35063},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1990__109_2_178463/}
}