Most were reprints of Edgar Rice Burroughs novels on which the copyright had lapsed , but in April 1963 , the firm acquired the rights to unpublished Burroughs manuscripts .
Under that imprint , Biblo and Tannen published a line of Burroughs books .
Most were reprints of Burroughs     novels on which the copyright had lapsed , but in April 1963 , the firm acquired the rights to unpublished Burroughs manuscripts .
Under that imprint , Biblo and Tannen published a line of Burroughs books .