Ámbito geográfico
UNITED STATES
10
DEVELOPING COUNTRIES
5
LATIN AMERICA
4
ESTADOS UNIDOS
3
RUSSIA (FEDERATION)
3
CHINA
2
COMMUNIST COUNTRIES
2
EUROPE
2
AMÉRICA LATINA
1
ARGENTINA
1
BRAZIL
1
CANADA
1
EAST ASIA
1
EUROPE, EASTERN
1
GERMANY
1
HUNGARY
1
INDIA
1
JAPAN
1
PAÍSES COMUNISTAS
1
PAÍSES EN DESARROLLO
1
POLAND
1
SOUTHERN CONE OF SOUTH AMERICA
1
SOVIET UNION
1