@article{MET_1991__38_2_176371,
     author = {A. Shapiro and M.W. Browne},
     title = {Invariance of {Covariance} {Structures} {Under} {Groups} of {Transformations.}},
     journal = {Metrika},
     pages = {345--355},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {1991},
     zbl = {0757.62004},
     url = {http://geodesic.mathdoc.fr/item/MET_1991__38_2_176371/}
}