Genre
Sources
73
Archives
71
Periodicals
25
Statistics
22
Congresses
17
Handbooks, manuals, etc
13
Personal narratives, British
5
Diaries
4
Bibliography
2
Electronic books
2
Public opinion
2
Surveys
2
Anecdotes
1
Case studies
1
Catalogs
1
Correspondence
1
Dictionaries
1
Encyclopedias
1
Gt. Brit
1
Laboratory manuals
1
Periodiques
1
Use studies
1
bibliography
1