00345nam a2200121Ia 4500082001900000100002500019245006800044260003500112300002000147490004600167500000500213700000500218  a515.1bEn57.FC  aEngelsman, Steven B.  aFamilies of curves and the origins of partial differentiationb  aAmsterdambNorth-Hollandc1984  aix, 238p. Bibl.  aNorth-Holland Mathematics studiesv v. 93  a  a