Final answer:
Dean can find public domain books for his jazz history research on Project Gutenberg, ask a campus librarian for assistance, or utilize academic databases such as Academic OneFile from Gale and Academic Search Complete from EBSCOhost. Inter-library Loan services may also be helpful if specific materials are not readily available.
Step-by-step explanation:
Dean can find legal copies of full-text books in the public domain for researching the history of jazz through various resources. One prominent source is Project Gutenberg, which is a volunteer effort to identify public domain works and make them freely available.
Additionally, if Dean has access to a college campus library, he can consult the librarian for help in finding primary sources that are in the public domain. Academic databases such as Academic OneFile from Gale and Academic Search Complete from EBSCOhost are also valuable resources, which can provide citations, abstracts, and sometimes full texts on a variety of subjects including the arts and literature.