@article{MZ_1972__129_171821,
     author = {Hubert Kalf},
     title = {A {Limit-Point} {Criterion} for {Separated} {Dirac} {Operators} and a {Little} {Known} {Result} on {Riccati's} {Equation.}},
     journal = {Mathematische Zeitschrift},
     pages = {75--82},
     publisher = {mathdoc},
     volume = {129},
     year = {1972},
     zbl = {0272.34035},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__129_171821/}
}