To overcome this problem the most widely adopted principle
in devising an author mark (either by letters or by author number)
is to follow bibliographic practice and to look for the heading of the
catalogue description. The first word of the heading of the
bibliographical description is usually the most useful access point
and the best choice for devising a book number. When the heading
is the author’s surname then we will create what is an author
number proper. Similarly and by following one’s country’s national
cataloguing rules for anonymous works, the heading may be either
the title or the editor. So, one should note that, in principle, national
cataloguing rules will guide and help create rules for book
numbering practice, as they will draw attention to issues that are
already well known and handled in the process of catalogue
heading selection. Here are some widely known problems: