@article{RCM_1969__3_181570,
     author = {R. W. Sandoval},
     title = {Partial differential equations with non-homogeneous boundary conditions},
     journal = {Revista colombiana de matematicas},
     pages = {1--21},
     publisher = {mathdoc},
     volume = {3},
     year = {1969},
     zbl = {0198.13903},
     url = {http://geodesic.mathdoc.fr/item/RCM_1969__3_181570/}
}