Plane trigonometry : a modern approach / Gabuyo, Yonardo A. ; Mejia, Leila D.P. - 2nd ed. - Manila : Rex Book Store, Inc., 2011. - ix,324 p.; 25.2cm. includes glossary, index, references ISBN: 9789712361326 Dewey Class. No.: Fil 516.242 G119 2011