@article{10_4153_CJM_1974_031_8,
     author = {Butler, G. and Macki, J. W.},
     title = {Oscillation and {Comparison} {Theorems} for {Second} {Order} {Linear} {Differential} {Equations} with {Integrable} {Coefficients}},
     journal = {Canadian journal of mathematics},
     pages = {294--301},
     year = {1974},
     volume = {26},
     number = {2},
     doi = {10.4153/CJM-1974-031-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1974-031-8/}
}