An annotated bibliography is a list of citations to books, articles, and documents just like the bibliography at the end of a paper. However, the "annotated part, is followed a brief (in this case around 3 sentences) descriptive and evaluative paragraph to inform the reader of the relevance, accuracy, and quality of the sources cited.
⇒this page shows you sample annotations. Scroll down for the APA format example.
Cornell University- Annotated Bibliographies-
⇒a How-To for creating an annotated bibliography including examples as well as further explanations on the process.