1. G. Chatelet and H. Rosenberg: Manifolds which admit Rn actions (to appear).
2. G. Joubert and R. Moussu: Feuilletage sans holonomie d'une variété fermée, C.r. Acad. Sci. Paris 270.
3. S. P. Novikov: Topology of foliations, Trudy Mosk. Maths. Obs hch 14, No. 513–83.
4. Foliations by planes;Rosenberg;Topology,1968