Hints that administrative law may be part of your research:
If you think you might be dealing with administrative law, consult a treatise or agency manual to confirm your hunch:
Review your chosen agency's website for links to primary law.
Research usually involves the CFR (Code of Federal Regulations) - the current code.
If you're not finding what you need, consult a guide to Administrative Law Research.
Some highly-regulated practice areas have specialized resources bringing together primary and secondary sources. Some are in Bloomberg Law's "Practice Centers."