Code of Federal Regulations is annual publication of current regulations. Check index by subject or agency for references to title and section. Update with List of Sections Affected and daily Federal Register. Publications patterns in states vary. Don't expect to find your exact situation in a previous case.
Lawyers use precedents by analogizing current situation to previous cases.
Demonstrate how they are alike on the crucial points and why the dissimilarities are not dispositive. Revisit the commentaries for a review and more depth of understanding.