All business with the Office must be transacted in writing. The action of the Office will be based exclusively on the written record. No consideration will be given to any alleged oral promise, stipulation, or understanding when there is disagreement or doubt.
37 C.F.R. §2.191
Part 3 pertaining to both patents and trademarks is placed in the grouping pertaining to patents regulations.
Part 4 is placed in the separate grouping of parts pertaining to patents regulations.
Part 5 is placed in the separate grouping of parts pertaining to patents regulations.