@article{10_4153_CMB_1993_024_9,
     author = {Headley, V.B.},
     title = {Comparison {Theorems} for {Linear} {Elliptic} {Equations}},
     journal = {Canadian mathematical bulletin},
     pages = {164--172},
     year = {1993},
     volume = {36},
     number = {2},
     doi = {10.4153/CMB-1993-024-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1993-024-9/}
}