2Maurice Leven. Entrepreneurial and Property Income and Income from Miscellaneous Sources[M]. Income in the Various States : Its sources and Distribution, 1925 : 221-249.
3Daniel Creamer, Martin Bernstein. Cycle in types of property income[M]. Personal Income During Business Cycles, 1956 :60-76.
4Maurice Leven. Entrepreneurial and Property Income and Income from Miscellaneous Sources[M]. Income in the Various States: Its sources and Distribution,1925:221-249.
5Daniel Creamer, Martin Bernstein. Cycle in types of property income[M]. Personal Income During Business Cycles,1956:60-76.
