Margaret Albright Knittl, «The design for the initial drainage of the Great Level of the Fens : an historical whodunit in three parts», Agricultural History Review, 55:1 (2007), pp. 23-50. AbstractԱրխիվացված 2011-07-21 Wayback Machine
Margaret Albright Knittl, «The design for the initial drainage of the Great Level of the Fens : an historical whodunit in three parts», Agricultural History Review, 55:1 (2007), pp. 23-50. AbstractԱրխիվացված 2011-07-21 Wayback Machine