Plane Trigonometry by Gustafson and Frisk (1993, Hardcover Vintage Textbook

College Algebra by R. David Gustafson and Peter D. Frisk (2003, Hardcover)

Intermediate Algebra 5e by: R. David Gustafson, Peter D. Frisk

College Algebra Textbook 4th Ed by R. David Gustafson & Peter D. Frisk Hardcover

College Algebra by R. David Gustafson and Peter D. Frisk 4th edition

Elementary Plane Geometry; Gustafson, R. David and Peter D. Frisk:

Beginning Algebra, Non-Media Edition by R. David Gustafson; Peter D. Frisk

Elementary Geometry by Gustafson, R. David; Frisk, Peter D.