00281nam a2200121Ia 4500082001700000100001800017245004000035260002500075300001000100490003900110500000500149700000500154  a516bP689.CC  aPittie, H. V.  aCharacteric classes of foliationsb  aLondonbPitmanc1976  a107p.  aResearch notes in Mathematicsv 10  a  a