@article{CMH_1987__62_140082,
     author = {S. Halperin and Luchezar Avramov},
     title = {On the non-vanishing of cotangent cohomology.},
     journal = {Commentarii mathematici Helvetici},
     pages = {169--184},
     publisher = {mathdoc},
     volume = {62},
     year = {1987},
     zbl = {0624.13013},
     url = {http://geodesic.mathdoc.fr/item/CMH_1987__62_140082/}
}