Reference books on slavery worldwide can be found in the REF. HT 861 section:
Books on slavery in the United States will be in the REF. E 441-450 area, such as:
For information on sex trafficking specifically, try this title in REF. HQ 115:
There are also entries on sex trafficking and trafficking of women in some titles in REF. HQ 1115:
Also see this title in REF. HV 6250.3 for human trafficking in general:
Some online reference sources for information on slavery in the United States:
Sources for reference information on worldwide slavery (past and present):