Dubrovin, B.A. Modern geometry-methods and applications, pt. I : the geometry of surfaces transformation groups, and fields - 2nd ed. - New York Springer 1992 - xv, 468p. ; 24cm. - Graduate texts in mathematics, 93 . ISBN: 9780387976631 Subjects--Index Terms: Mathematics Geometry Dewey Class. No.: 516 / DUB.pt.1