66.228 5r 109 Instant

"66.228" could be a section number. The format with a decimal might be similar to how some codes are organized. Then "5r" could be a subsection or a note. "109" might be another section number or part of a citation to a specific part of the code. Maybe it's part of the Internal Revenue Code, which uses a different format, though. For example, the Internal Revenue Code uses 26 U.S.C. followed by the section number. But here, 66 is more likely to be in other codes. Let me check the Internal Revenue Code—no, 66 is in there, like 26 U.S.C. §6662, which is about penalties for tax understatements. But that's 66.62, not 66.228.