@article{AM2_1997__54_3_137703,
     author = {Z. P\'ales and S.S. Dragomir and B. Mond},
     title = {On a superadditivity property of {Gram's} determinant.},
     journal = {Aequationes mathematicae},
     pages = {199--204},
     publisher = {mathdoc},
     volume = {54},
     number = {3},
     year = {1997},
     zbl = {0890.26015},
     url = {http://geodesic.mathdoc.fr/item/AM2_1997__54_3_137703/}
}