Words used in this part in the singular form shall be considered to import the plural, or vice versa, as the case may demand. [31 FR 4687, Mar. 19, 1966; 31 FR 4949, Mar. 25, 1966; Redesignated at 42 FR 32514, June 27, 1977 and at 46 FR 63203, Dec. 31, 1981]