@article{MAN_1972__197_162263,
     author = {William H. Courage and William J. Davis},
     title = {A {Characterization} of {M-Bases.}},
     journal = {Mathematische Annalen},
     pages = {1--4},
     publisher = {mathdoc},
     volume = {197},
     year = {1972},
     zbl = {0216.40803},
     url = {http://geodesic.mathdoc.fr/item/MAN_1972__197_162263/}
}