“Where Does it Say That?” is a popular anti-Mormon book produced by Bob Witte; an online version can be found here. Of course, as with any publication associated with the Institute of Religious Research, it lacks scholarly acumen.
Elden Watson, a long-standing student and researcher of LDS history and theology, has written a review of Witte’s publication, which shows the gross inaccuracies and sloppy methodology thereof. Issues discussed include allegedly false prophecies of Joseph Smith, the LDS understanding of God, and the First Vision.