Genre
Electronic books
419
Periodicals
275
Maps
157
Congresses
82
Educational films
45
Electronic journals
45
Documentary films
37
Science films
37
Guidebooks
33
Bibliography
31
Libros electronicos
30
Documentary television programs
27
Early works to 1800
23
Biography
21
Juvenile literature
18
Charts, diagrams, etc
12
Electronic book
12
Popular works
12
Science television programs
12
Atlases
9
Geological maps
7
Pictorial works
7
Publicaciones periodicas
7
Abstracts
6
Encyclopedias
5
Indexes
5
DVD-Video discs
4
Nonfiction television programs
4
Surveys
4
Children's films
3
Dictionaries
3
Geological cross-sections
3
Handbooks, manuals, etc
3
Miscellanea
3
Video recordings for the hearing impaired
3
Databases
2
Diaries
2
In art
2
Literatura infantojuvenil
2
Nomenclature
2
Outlines, syllabi, etc
2
Short films
2
Sources
2
Tables
2
Textbooks
2
Aerial photographs
1
Aerial views
1
Anecdotes
1
Annals and chronicles
1
Bathymetric maps
1
more ...