41 C.F.R. § 101-1.109
(a) In the numbering system, all FPMR material is preceded by the digits 101-. This means that it is chapter 101 in title 41 of the Code of Federal Regulations. It has no other significance. The digit(s) before the decimal point indicates the part; the digits after the decimal point indicate, without separation, the subpart and section. For example:

[54 FR 37652, Sept. 12, 1989]