The Bourne Archive
Colby, Baker et. al. Ordnance Survey, Sheet 70, Sleaford,
facsimile edition, Reprint of the first edition of the one-inch Ordnance Survey of England and Wales, Sheet 36, Sleaford, David & Charles (1970)
ISBN 0 7153 4837 X
1 inch to 1 mile scale sheet 585 x 890 mm with notes by J.B.Harley. Monochrome electrotype from copper plate.