- Libro electrónicoThe 1997 CIA World FactbookUnited States. Central Intelligence Agency
- Libro electrónicoThe 1994 CIA World FactbookUnited States. Central Intelligence Agency
- Libro electrónicoThe 1991 CIA World FactbookUnited States. Central Intelligence Agency
- Libro electrónicoThe 1995 CIA World FactbookUnited States. Central Intelligence Agency