Although trading in these book and magazine numbers is technically illegal, foreign firms (including Taiwanese) have been able to utilize private back channels (that is, channels not affiliated with the official Xinhua Bookstore) to acquire book numbers.
儘管書號、刊號買賣並不合法，但包括台灣等外資進入，卻多是以透過新華書局官方之外的民間發行「二渠道」買到書號切入。