@article{ARM_1986__22_2_a1,
     author = {M\"uller-Pfeiffer, Erich},
     title = {Comparison theorems for {Sturm-Liouville} equations},
     journal = {Archivum mathematicum},
     pages = {65--73},
     publisher = {mathdoc},
     volume = {22},
     number = {2},
     year = {1986},
     mrnumber = {868121},
     zbl = {0632.34029},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1986__22_2_a1/}
}