Relations between textbook publishers and college booksellers have been seriously by the issue. "This has become a very hot issue since last year. when just seemed to explode all of a sudden." said Ms. Nakoneczny, of the college store association. The association's letter publishers warned that the pricing structure might be an antitrust violation. "The sale of identical books to foreign buyers at prices that significantly lower than to domestic buyers, while publicly stating that domestic prices are due to high costs, could constitute an unfair or deceptive act," the letter said. While there is no longer protection in the federal copyright law for the pricing differentials, the major publishers are still trying to stop the reimporting of texts priced for foreign markets, mostly through contract language forbidding foreign wholesalers to sell to american distributor. Some have placed stickers on covers, saying "International Edition RESTRICTED Not for sale in North America" or added the cover line "International "International Student Edition.