Transactions of the Woolhope Naturalists’ Field Club, Hertfordshire. Volume for 1936, 1937 and 1938
Reference: Morgan, 1940
Frederick Charles Morgan, 'Early Water Colour Drawings of Hereford Cathedral', Transactions of the Woolhope Naturalists’ Field Club, Hertfordshire. Volume for 1936, 1937 and 1938, Hereford, 1940