37 C.F.R. § 1.436 The claims.
Title 37 - Patents, Trademarks, and Copyrights
The requirements as to the content and format of claims are set forth in PCT Art. 6 and PCT Rules 6, 9, 10 and 11 and shall be adhered to. The number of the claims shall be reasonable, considering the nature of the invention claimed.
Title 37: Patents, Trademarks, and Copyrights
PART 1—RULES OF PRACTICE IN PATENT CASES
Subpart C—International Processing Provisions
The International Application
§ 1.436 The claims.

