The geology of parts of Cambridgeshire and of Suffolk (Ely, Mildenhall, Thetford) : (Explanation of Sheet 51 N.E. with part of 51 N.W.) - Woodward, Horace B. (Horace Bolingbroke), 1848-1914; Whitaker, W. (William), 1836-1925 (Memoirs of the Geological Survey of Great Britain. England and Wales., 1891)