divisions of geography. Another pre-war concept that combined elements of sociology and geography was the one established by Dutch sociologist Sebald Rudolf Steinmetz and his Amsterdam School of Sociography. However, it lacked a definitive subject, being a combination of geography and ethnography created as the more concrete counterpart to the rather theoretical sociology. In contrast, the Utrecht School of Social geography, which emerged in the early 1930s, sought to study the relationship between social groups and their living spaces. Post-War Period Continental Europe In the German-language geography, this focus on the connection between social groups and the landscape was further developed by Hans Bobek and Wolfgang Hartke after the Second World War. For Bobek, groups of Lebensformen (patterns of life)—influenced by social factors—that formed the landscape, were at the center of his social geographical analysis. In a similar approach, Hartke considered the landscape a source for indices or traces of certain social groups' behaviour. The best-known example of this perspective was the concept of Sozialbrache (social-fallow), i.e. the abandoning of tillage as an indicator for occupational shifts away from agriculture. Though the French Géographie Sociale had been a great influence especially on Hartke's ideas, no such distinct school of thought formed within the French human geography. Nonetheless, Albert Demangeon paved the way for a number of more systematic conceptualizations of the field with his (posthumously published) notion that social groups ought to be within the center of human geographical analysis. That task was carried out by Pierre George and Maximilien Sorre, among others. Then a Marxist, George's stance was dominated by a socio-economic rationale, but without the structuralist interpretations found in the works of some the French sociologists of the time. However, it was another French Marxist, the sociologist Henri Lefebvre, who introduced the concept of the (social) production of space. He had written on that and related topics since the 1930s, but fully expounded it in La Production de L'Espace as late as 1974. Sorre developed a schema of society related to the ecological idea of habitat, which was applied to an urban context by the sociologist Paul-Henry Chombart de Lauwe. For the Dutch geographer Christiaan van Paassen, the world consisted of socio-spatial entities of different scales formed by what he referred to as a "syn-ecological complex", an idea influenced by existentialism. A more analytical ecological approach on human geography was the one developed by Edgar Kant in his