1. American Economic Association . 1886 . Report on organization of the American Economic Association . Publications of the American Economic Association1st series, 1:5 -32 .
2. R. P. Beckinsale, 1981 . W. M. Davis and American geography: 1880-1934 . InBlouet and Stitcher1981, pp.107 -22 .
3. Commercial Geography as a Science. Reflections on Some Recent Books