1. Farm practices in growing winter wheat;U. B. Department of Agriculture Year Book,1919
2. Arable land in the United State;U. B. Department of Agriculture Year Book,1918
3. Experiment Station Record 42: 617 (1919).
4. Garner, W. W., Journal of Agricultural Research 18: 553 (1920).
5. Delaware Agricultural Experiment Station Bulletin 1917 117 The tillering of winter wheat