Genre
Electronic books
17
Bibliography
11
Directories
10
Congresses
8
Handbooks, manuals, etc
6
Databases
5
Case studies
3
Pictorial works
3
Catalogs
2
Problems, exercises, etc
2
Archives
1
Biography
1
Conference papers and proceedings
1
Film catalogs
1
Genealogy
1
Indexes
1
Statistics
1
Surveys
1
Use studies
1