@article{10_4153_CJM_1967_011_7,
     author = {Howard, H. C.},
     title = {Oscillation {Criteria} for {Matrix} {Differential} {Equations}},
     journal = {Canadian journal of mathematics},
     pages = {184--199},
     year = {1967},
     volume = {19},
     number = {1},
     doi = {10.4153/CJM-1967-011-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1967-011-7/}
}