"Naturressourcer" . . "Economic history." . . "Since 1960" . . "Udviklingspolitik" . . "Populationsdynamik" . . "Africa, Sub-Saharan" . . "Africa, Sub-Saharan." . "Afrique noire" . . "Environmental policy." . . "Development policies" . . "Economic development" . . "Schwarzafrika" . . "Subsaharisches Afrika." . . . . "Consultative Group on International Agricultural Research (Washington, D.C.)" . . "Natural resources" . . "Africa" . . "Africa" . . "Environmental policy Africa, Sub-Saharan." . . . . . . . . . . . "The challenges for sub-Saharan Africa : Sir John Crawford memorial lecture" . . "Le développement africain : tâches et possibilités" . . . . . . . . . "The challenges for sub-saharan africa : Sir John Crawford memorial lecture" . . . . . . "The challenges for sub-Saharan Africa"@en . "The challenges for sub-Saharan Africa" . . "The challenges for sub-saharan Africa" . . "The challenges for Sub-Saharan Africa"@en . . "The challenges for Sub-Saharan Africa" . . . . . . . . . . . . . . "Le développement africain tâches et possibilités" . . . "Challenges for Sub-Saharan Africa" . . . . . . . . . . . . . . . . . . . "Population dynamics" . . "Population policy." . . "Økonomisk udvikling" . . "Afrika" . . "Afrika" . . "Sozioökonomischer Wandel" . . "Sozioökonomischer Wandel." .