Administrative agencies at both the state and federal level produce a prodigious amount of official materials, be it regulations or agency court opinions. Note: a lot of law is regulatory driven, mainly because each legislature does not have the time to micro-manage and legislate each agency's rules.
As such, it pays to familiarize yourself with the main agencies and their documentations of the federal government, and the state you are in.
Rule 14 and especially, Table 1, give examples and rules on how to cite (and in reserve, interpret a cite) administrative materials.
Remember that the C.F.R. and other federal regulatory documents have an "authenticated certificate," thereby allowing a citation from the online version as if to "the original print source," (Rule 18.2.1(a)).
9 C.F.R. § 300.1 (2011)
610 Mass. Code Regs. 6.01 (2013)
Superior Trading v. Commissioner, 137 T.C. 70 (2011)
Note: as with anything in the bluebook, remember your typeface conventions (Rule 2 & Bluepages Rule 1).
Remember your spacing - no spaces between the C.F.R. in the cite to the Code of Federal Regulations. Remember to cite to the correct version you are looking at. It is often the case that an older version of a regulatory code is required, and remember to cite to the correct year.
Generally, follow the format as your would for non-administrative cases and arbitrations - see Rule 10. Also note the short-forms specified in Rule 14.5.
Executive orders issued by the President are reprinted in the Code of Federal Regulations, (C.F.R). Cite to the edition of the C.F.R. in which the executive order is first printed (See T1, United States Jurisdiction, page 237). The Federal Register also prints executive orders, and may be cited to if an executive order has yet to be printed in the C.F.R..
Executive orders issued by a governor of a state should be handled according to the guidelines of the state. This frequently mimics the federal level, with orders from the executive office first being published in the state equivalent of the federal register (for example, the Massachusetts Register) then subsequently the code of regulations for that state (like the Code of Massachusetts Regulations).
For peculiar instances, like pandemic-related orders, “citing to an agency or governmental website is appropriate,” when orders are not printed in either the appropriate register or code of regulation (Rule 14.2(b)).