Does the information relate to your topic? Does it answer your questions?
Who is the intended audience? Is the information at an appropriate level for your needs (that is, not too elementary or advanced)?
Thom Holmes's Dawn of the Dinosaur Age is the first volume in a 10-volume set devoted to the prehistoric earth. The author notes in his introduction that the entire series "is written for readers in high school."
Earthquakes: Plate Tectonics and Earthquake Hazards includes a bibliography titled "Further Reading and Web Sites" and a glossary. Author Timothy Kusky writes in his preface that the book is intended for "middle- and high-school students and college students."
Cancer Research is one of the world's leading cancer journals. Its OnlineFirst section includes articles that have been accepted for publication, "but not yet copyedited or typeset, allowing readers the most rapid access to accepted papers."
Art History Resources is maintained by Chris Whitcombe, a professor of art history at Sweet Briar College. A reviewer writes that Witcombe "has perhaps the best organized gateway to art history sites on the Web. His directory is chock-full of useful and regularly updated links."