An annotated bibliography is a list of citations to books, articles, and documents. Each citation is followed by an annotation, a brief (usually about 150 words) descriptive and evaluative paragraph. The annotation informs the reader of the relevance, accuracy, and quality of the sources cited.
"A bibliography in which a brief explanatory or evaluative note is added to each reference or citation. An annotation can be helpful to the researcher in evaluating whether the source is relevant to a given topic or line of inquiry." (Dictionary of Library and Information Science, 2004)
Abstracts are the purely descriptive summaries often found at the beginning of scholarly journal articles.
Annotations are descriptive and critical, describing the author's authority, point of view, as well as the scope and purpose of the source.
Provides definitions about, reasons for, and formats and examples of annotated bibliographies. Written by Dana Bisignani and Allen Brizee from The Writing Lab & The OWL at Purdue, Purdue University.
This handout will explain why annotated bibliographies are useful for researchers, provide an explanation of what constitutes an annotation, describe various types of annotations and styles for writing them, and offer multiple examples of annotated bibliographies in the MLA, APA, and CBE/CSE styles of citation." From The Writing Center, the University of North Carolina at Chapel Hill.
This site includes examples of different kinds of annotations including informative, indicative, and evaluative. UW-Madison's "Writer's Handbook" has lots of helpful advice for the entire writing process.
Helpful guides to citation styles: