When the date of the publication is not in brackets, it means that the
same will be found on title page. When, however, it is in brackets,
thus, (1931), it indicates that said date is printed either on the
reverse side of title page, or in some other part of the book. Or,
possibly, the date does not appear at all, in which case the brackets
are merely authoritative information supplied by the bibliographer.
Furthermore, our endeavor has been to list only authors and books for
which there is a reasonably active present-day demand, and which have a
speculative future.