Once open access started to be introduced more widely in
European libraries, the arrangement of books within the class was
chosen based on various combinations of national traditions and
remained a matter of localized practice and in-house rules not all
of which found their way into library textbooks (Slavic, 1997).
When dealing with systematic arrangement in open access,
European libraries have all adopted the good practices introduced
and tested long ago in Anglo-American librarianship: classification
(Dewey, UDC or other) and structured book numbers within class
arrangement. Still, European librarians will be more familiar with
the practice of double call numbers: one for closed stacks and one
for open access, and would consider both of them equal relevance
in collection management