Region
United States
1,803
États-Unis
412
Great Britain
127
Pennsylvania
103
China
61
Canada
55
Soviet Union
46
England
41
Japan
41
Ireland
33
Europe
32
USA
29
Germany
26
Russia (Federation)
25
New Jersey
24
Grande-Bretagne
23
France
22
North America
19
Latin America
17
New York (State)
17
Developing countries
16
Australia
15
Brazil
15
California
15
Amérique du Nord
12
Scotland
12
Foreign countries
11
Irlande
11
Bolivia
10
Englisch
10
Handbooks, manuals, etc
10
Ohio
10
Pennsylvanie
10
London
9
Peru
9
Philadelphia
9
Poland
9
United States, Pennsylvania
9
Washington (D.C.)
9
Colombia
8
European Economic Community countries
8
New York (N.Y.)
8
Ecuador
7
Großbritannien
7
Italy
7
London (England)
7
Massachusetts
7
Michigan
7
Spain
7
Texas
7
more ...