THE COUNTY MAPS OF OLD ENGLAND
By Thomas Moule
Published by Studio Editions 1990
Originally Published in 1830 as "The English Counties Deliniated"
ISBN 1-85170-403-5
Essex Map - page 47

READER'S DIGEST TOURING GUIDE TO BRITAIN
ISBN 0-276-42031-4
The Thames Estury - page 85

READER'S DIGEST COMPLETE ATLAS OF THE BRITISH ISLES
Section One - The Nature of the Land
Southern England and South Wales
Page 8