Russell Stover is a candy manufacturer that ships its products to 18,000 retailers nationwide. Stover designates resale prices for its dealers but does not request assurances from them that they are honoring the prices. It has, however, refused to sell to those retailers it believes will sell below the prices suggested. Is there an antitrust violation in this conduct? [Russell Stover Candies, Inc. v FTC, 718 F.2d 256 (8th Cir. 1982)]