@article{MAN_1976__220_162822,
     author = {H.R. Dowson and T.A. Gillespie and P.G. Spain},
     title = {A {Commutativity} {Theorem} for  {Hermitian} {Operators.}},
     journal = {Mathematische Annalen},
     pages = {215--218},
     publisher = {mathdoc},
     volume = {220},
     year = {1976},
     zbl = {0305.47014},
     url = {http://geodesic.mathdoc.fr/item/MAN_1976__220_162822/}
}