1. Drainage of heavy soils;FAO,1971
2. The Principles of Field Drainage;Nicholson,1942
3. The effects of surcharging in the underdrainage system on mole drainage;Whitmore,1987
4. The draining of farm lands;Hudson,1962
5. Summary of field observations: Scredington, Lincolnshire 1965–71;Twocock,1971