The general rules for citing administrative and executive materials can be found in Bluebook Rule 14. Most of Rule 14 describes citing federal materials, but Rule 14.4 specifically describes citing state materials. Table T1.2 provides unique citation formats for some specific federal agencies. Table T1.3 gives the formats for citing state administrative compilations (codified final rules and regulations) and administrative registers (rulemaking materials and information prior to codification).
Rule 14.2(d) describes how to cite to "other publications" from administrative agencies or executive offices. This category would include most materials such as reports, fact sheets, and pamphlets.
Federal Rules and Regulations
Code of Federal Regulations
Federal Register
State Rules and Regulations
Lexis and Westlaw will generally have state regulations from the early 1990s through the present (the exact dates covered vary by state). Speak with a reference librarian for additional assistance in locating state regulations.
Citations for agency adjudications and arbitrations will looks similar to cases. There is no single, centralized location for these materials at either the federal or state levels but Lexis and Westlaw each will have some. If Lexis and Westlaw do not have the materials you are looking for, try checking the agency's website.
The best place to look for most agency and executive materials is on the agency's website. Rather than using an agency website's internal search engine, you may have better results with a Google Advanced Search with the website's URL in the "site or domain" field.
For older agency and executive materials, especially from a prior presidential administration, you may need to find an archival version. The Internet Archive's Wayback Machine includes an extensive collection of archived government websites.