000			003280000a22001330004500
245			_aTurtle geometry : computer as a medium for exploring mathematics
100			_aAbelson, H.
100			_aDisessa, A.A.
260			_aCambridge _bMIT _c1980
020			_a0-262-01063-1
080			_a514 _bA2
041			_aEN
942			_cBK
999			_c120282 _d120282