Genre
Maps
22
Periodicals
9
Technical reports
7
Conference papers and proceedings
6
Observations
6
Annual reports
5
Bathymetric maps
5
Statistics
5
Remote-sensing maps
4
Atlases
3
Handbooks and manuals
3
Legislative materials
3
Classification
2
Treaties
2
Bibliographies
1
Case studies
1
Charts, diagrams, etc
1
Congresses
1
Geological maps
1
Graphs
1
Identification
1
Laboratory manuals
1
Photographs
1