@article{CMH_1976__51_139646,
     author = {Arthur J. Ledger and R. Bruce Pettitt},
     title = {Compact {Quadratic} {s-Manifolds}},
     journal = {Commentarii mathematici Helvetici},
     pages = {105--132},
     publisher = {mathdoc},
     volume = {51},
     year = {1976},
     zbl = {0323.53038},
     url = {http://geodesic.mathdoc.fr/item/CMH_1976__51_139646/}
}