( 1) Ordnance Survey Map (Scale / Date)
OS 6" 1960
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( 2) Field Investigators Comments
F1 ASP 10-OCT-69
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( 3) Ordnance Survey Archaeology Division Object Name Book reference
Herts ONB, Rev.1922, 12 SW, p8.
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( 4) General reference
Mediaeval Castles in Hertfordshire 1971 (D Renn)
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