00323nam a2200121 a 450000500170000002000150001710000220003224500390005426000350009330000260012849000340015463000130018820251202164229.0  a0805394850  aWallace, Andrew H  aDifferential topology: first steps  aLondonbenjamin/Cummingsc1968  axi, 130 p.b22 cm.c_  aMathematics Monographs series  aTopology