What are the main theories that have been proposed and the main methods that have been used? -What are the puzzles/themes that have been developed?

What effects does immigration have on the US economy.

Human rights and social justice synthesis research paper. Annotated bibliography for the topic. Bibliography should include at least 15 books and/or peer-reviewed journal articles. Provide an annotation for each source that consists of three paragraphs/parts 1) summary of the thesis, major arguments and methodology of the source; 2) Potential counterarguments and/or your own critique and assessment of the source; and 3) Paragraph speculating on a possible application.

Afterwards you should use 1-2 pages (single spaced) to synthesize your research by answering the following questions:
-What are the main theories that have been proposed and the main methods that have been used?
-What are the puzzles/themes that have been developed?
-What are the gaps? What should be further explored? What should be the direction for future research this topic?