Travel and tourism under pandemic conditions review and preparation exercise Madrid, Spain, & World Tourism Organization. (2009). Travel and tourism under pandemic conditions: Review and preparation exercise : UNWTO Headquarters, Madrid, Spain, 26-27 August 2009. World Tourism Organization.
Παραπομπή σε μορφή Chicago (17η εκδ.)Travel and tourism under pandemic conditions review and preparation exercise Madrid, Spain, και World Tourism Organization. Travel and Tourism Under Pandemic Conditions: Review and Preparation Exercise : UNWTO Headquarters, Madrid, Spain, 26-27 August 2009. Madrid, Spain: World Tourism Organization, 2009.
Παραπομπή σε μορφή MLA (9th εκδ.)Travel and tourism under pandemic conditions review and preparation exercise Madrid, Spain, και World Tourism Organization. Travel and Tourism Under Pandemic Conditions: Review and Preparation Exercise : UNWTO Headquarters, Madrid, Spain, 26-27 August 2009. World Tourism Organization, 2009.