You may need to use keywords like multiculturalism, diversity, minorities and related terms to find books on this topic. Check out the book Identity Development of College Students: Advancing Frameworks for Multiple Dimensions of Identity.
There are encyclopedias on various ethnic groups and minorities such as the following:
Encyclopedia of Women and Gender
Encyclopedia of Language and Education
Encyclopedia of Religion
Encyclopedia of Disability
The Encyclopedia of African-American Education
Historically Black Colleges and Universities: An Encyclopedia.
Encyclopedia of Black Studies
The Oxford Encyclopedia of Latinos and Latinas in the United States
Encyclopedia of American Indian History
Encyclopedia of Lesbian, Gay, Bisexual, and Transgender history in America.
Multicultural America: An Encyclopedia of the Newest Americans