Ledford, Jerri L. Search engine optimization bible / Jerri L. Ledford - 2nd ed. - Indianapolis, IN : Wiley Pub., 2009 - xx, 507 p. : ill. ; 24 cm. ISBN: 9780470452646 RM109.91 Subjects--Topical Terms: Web search enginesWeb sites--DesignWeb sites--Ratings and rankings