@article{MM2_1994__83_3-4_155943,
     author = {M.G.C. Andrade and E.L.C. Fanti},
     title = {A {Relative} cohomological invariant for group pairs.},
     journal = {Manuscripta mathematica},
     pages = {1--18},
     publisher = {mathdoc},
     volume = {83},
     number = {3-4},
     year = {1994},
     zbl = {0837.20061},
     url = {http://geodesic.mathdoc.fr/item/MM2_1994__83_3-4_155943/}
}