APA (7th ed.) Citation

Harley, J. B. (1964). The historian's guide to Ordnance Survey maps. N.C.S.S..

Chicago Style (17th ed.) Citation

Harley, J. B. The Historian's Guide to Ordnance Survey Maps. N.C.S.S., 1964.

MLA (9th ed.) Citation

Harley, J. B. The Historian's Guide to Ordnance Survey Maps. N.C.S.S., 1964.

Warning: These citations may not always be 100% accurate.