Gaya APA

ICAO, . (1952). CIRCULAR 28-AT/4 EXISTING FORMS OF COMMERCIAL AND TECHNICAL CO-OPERATION BETWEEN EUROPEAN AIRLINES IN REGIONAL AIR SERVICES . Canada: ICAO.

Gaya MLA

ICAO, . "CIRCULAR 28-AT/4 EXISTING FORMS OF COMMERCIAL AND TECHNICAL CO-OPERATION BETWEEN EUROPEAN AIRLINES IN REGIONAL AIR SERVICES". Canada: ICAO, 1952. Text.