Classification
ZCA - Documentation
60
ZCB - Information science
6
ZAD - Book trade, publishing
5
ZCD - Information retrieval
4
ZBH - Digital library
3
ZBEBB - Subject indexing
2
ZCC - Information technology
2
ZEA - Archives
2
DMF - Software engineering
1
DNC - Internet
1
DVA - Data and file management
1
DWI - Information management
1
YNA - Patents, trademarks
1
YPB - Economy - general aspects
1
YRCD - Informatics, information and society
1
ZAB - Media studies (without bibliology)
1
ZBAB - Dictionaries
1
ZBAE - Conferences
1
ZBB - Library staff
1
ZBE - Library administration
1
ZBHB - Library networks
1
ZDA - Museums
1