These are the Library of Congress classification call numbers where you will find books shelved on the listed topics.
E184 - E185 African-American experience in the U.S.
E184 - E185 Reference Encyclopedias on African-American people, history, and events in the U.S.
PS153 Collections and anthologies of African-American literature in the U.S.
PS153 Reference Same as above plus fiction studies.
PS3500 American fiction authors including African-American authors.
You can also look up specific authors to see what we have by them.
Here's a few:
This list is from only the first page of a search done in the GHC - GIL online catalog using this search string: "(All Fields:african-american AND All Fields:literature)" and limiting to eBooks - there are plenty more.
Here is the eBook guide for help in using eBooks: E-Books and E-Readers Help.