11409<>6227_8<>nulo<>set-theoretical basis for real numbers<>jsyml<>hao wang<>
11412<>6227_11<>nulo<>a formal system of logic<>jsyml<>hao wang<>
11413<>6227_12<>nulo<>existence of classes and value specification of variables<>jsyml<>hao wang<>
