Study on the optimal situation of China's urban population Study on the fluctuation of China's cotton production Study on citizenization of rural migrant population Study on the ecosystem of enterprise population Study on the optimal scale of cities and urban agglomerations in China Study on the relations among sinicization, modernization and popularization Study on the economic integration of Chengdu-Chongqing urban agglomeration Studies on the local managing regulation of floating population Study on the employment of migrant agricultural population