@article{MOMA_1968__72_177414,
     author = {Paul Waltman and R.C. Grimmer},
     title = {A {Comparison} {Theorem} for a {Class} of {Nonlinear} {Differential} {Inequalities.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {133--136},
     publisher = {mathdoc},
     volume = {72},
     year = {1968},
     zbl = {0185.17603},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1968__72_177414/}
}