This disrupted plans for publishing any new volumes of "The Complete Works of Marx and Engels" that was already in progress. It also halted distribution of other ideological works. As late as 1970, more than 8 million copies of the 4-volume set of "Selected Works of Marx and Engels" that had already been printed (both in cloth hardcover and paperback) remained undistributed in storage warehouses on the grounds that other works "should not interfere with learning "Quotations from Chairman Mao Tse-Tung"".