The call numbers for customs law are around KF6690 in the Library. Browsing the shelves there may also help you find relevant secondary sources. Further, you can do a subject search in the library catalog. Possible subject headings to use would include:
To find articles on customs law, use the major legal indexes: Legal Periodicals and Books, LegalTrac, or Index to Foreign Legal Periodicals. Links to these and other databases are available from the library's page on legal periodicals.
There are a number of law journals in the library dealing with international trade. To find them, you can do a keyword search in our catalog for the words "international and trade," limited to the location "Journals".