Analysis of information sources in references of the Wikipedia article "Long Knoll" in English language version.
A Marilyn is a hill of any height with a drop of 150 metres or more on all sides. In other words, a relatively high hill. The Marilyns in Britain and the Isle of Man are listed in a book called The Relative Hills of Britain (RHB) by Alan Dawson, published by Cicerone Press in April 1992. Details of subsequent changes have been published in a series of updates.
