@article{MZ_1968__108_171084,
     author = {John J. Sember},
     title = {A {Note} on {Conull} {FK} {Spaces} and {Variation} {Matrices.}},
     journal = {Mathematische Zeitschrift},
     pages = {1--6},
     publisher = {mathdoc},
     volume = {108},
     year = {1968},
     zbl = {0165.38103},
     url = {http://geodesic.mathdoc.fr/item/MZ_1968__108_171084/}
}