37 CFR:

§ 1.57 Incorporation by reference.

(a) Subject to the conditions and requirements of this paragraph, a reference made in the English language in an application data sheet in accordance with § 1.76 upon the filing of an application under 35 U.S.C. 111(a) to a previously filed application, indicating that the specification and any drawings of the application under 35 U.S.C. 111(a) are replaced by the reference to the previously filed application, and specifying the previously filed application by application number, filing date, and the intellectual property authority or country in which the previously filed application was filed, shall constitute the specification and any drawings of the application under 35 U.S.C. 111(a) for purposes of a filing date under § 1.53(b).