(EN) PastScape - English Heritage National Monuments Record - Jullieberries Grave, su pastscape.org.uk. URL consultato il 23 marzo 2018.
"Jessup began his excavation at Julliberrie's Grave in July 1936 (see authority 2) inspired by the account of a fictional excavation of the site by Mr Elmhurst in R Austin Freeman's novel "The Penrose Mystery", published in 1936. Jessup had supplied technical advice and information for the novel."
