Oxford Bibliographies Online is a wonderful place to look for resources. The articles are all written by specialists in the field who organize the materials like an annotated bibliography. It will give you a good introduction to a topic, carefully organized to provide you with the most important works in the field. Here are some examples:
Chicana/o Art by Constance Cortez
Conceptual Art and Conceptualism by Robert Bailey has a section on "Internationality and Diaspora"
Contemporary Art by Terry Smith has some citations related to diaspora.
Biographies and Handbooks can be extremely useful in the beginning stages of a research project. Written by specialists in the field, they are a quick reference point for basic facts about an artist. Most of them also include a "further reading" section that is helpful for expanding your research into new areas.