Genre
Statistics
2,211
Periodicals
1,946
Maps
1,357
Technical reports
1,279
Handbooks and manuals
1,138
Treaties
879
Conference papers and proceedings
584
Databases
210
Bibliographies
169
Case studies
140
Directories
110
Census data
104
Catalogs
101
Dictionaries
100
Classification
87
Remote-sensing maps
86
Congresses
84
Topographic maps
63
Examinations
61
Biographies
60
Trivia and miscellanea
59
Video recordings
58
Legislative hearings
45
Tables (Data)
42
Remote-sensing images
41
Sound recordings
36
Graphs
35
Bathymetric maps
34
Guidebooks
31
Academic theses
26
Vital statistics
24
Blank forms
23
Posters
22
Educational films
21
Legislative materials
20
Calendars
19
Indexes
19
Pictures
19
Documentary films
18
Geographic information systems
18
Personal correspondence
18
Registers (Lists)
18
Observations
17
Identification
16
Illustrated works
16
Records (Documents)
16
Laboratory manuals
15
Literature
15
Photographs
15
Environmental impact statements
13
more ...