Geschiedeniswerkplaats / J. Beetsma. Leerlingenboek / J. Beetsma : 1: De koude oorlog Geschiedeniswerkplaats / J. Beetsma. Leerlingenboek / J. Beetsma : 5: Verenigde Staten 1917-1941 Field officer course : Intelligence-A Staff Function / Air University. Air command and staff school. Vol. 7: Intelligence Staff Division Field officer course : Production and Dissemination of Intelligence / Air University. Air command and staff school. Vol. 7: Intelligence Staff Division Field officer course : Special uses of intelligence / Air University. Air command and staff school. Vol. 7: Intelligence Staff Division