Angel, Allen R. Algebra elemental / Allen R. Angel / Richard Semmler / Donna R. Petrie - 6a Ed - Mexico : Pearson Educacion , 2007 - 667 p : il ISBN: 970-26-0775-2 Subjects--Topical Terms: Warren, Howard C. , 1867-1934 Dewey Class. No.: REF 512 ANG