@article{AM2_1982__25_136960,
     author = {H. Beker and Ch. Mitchell and F. Piper},
     title = {Tactical decompositions of designs.},
     journal = {Aequationes mathematicae},
     pages = {123--152},
     publisher = {mathdoc},
     volume = {25},
     year = {1982},
     zbl = {0521.05012},
     url = {http://geodesic.mathdoc.fr/item/AM2_1982__25_136960/}
}