From your instructor:
"For the annotated bibliography, students need 12 sources. Students must make use of the following four types of sources: books (at least two print or ebooks), periodicals (academic periodicals and/or scholarly journals), newspapers, and Web. Other types of sources may be used in addition to the above mentioned four."
It doesn't matter how good a source is or where you find it if that source doesn't match what you need. There are a few things that will impacts what you need and where to look: what your instructor wants you to use, how much time you have to get the source, and what kind of information it gives you.