Pub. L. 86-682, tit. 39, pt. IV, ch. 63, sec. 4361
Rates for proofs of advertisements
§ 4361. Rates for proofs of advertisements The publisher may mail single sheets or portions thereof from any publication entered as second class mail, to an advertiser or his agent as proof of the insertion of an advertisement, at the zone rates of postage applicable to the advertising portions of second class mail under section 4359 of this title.