@article{MZ_1972__126_171743,
     author = {William N. Everitt and Magnus Giertz},
     title = {Some {Inequalities} {Associated} with {Certain} {Ordinary} {Differential} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {308--326},
     publisher = {mathdoc},
     volume = {126},
     year = {1972},
     zbl = {0238.47029},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__126_171743/}
}