Document Trivia of Great Britain and Ireland - Official and Unofficial Designations on Paper and Parchment: Circular Date Marks, by W A Barber/A F Brown.

Published by the authors, 2007.  S/B, 34pp.

A study of the Circular Date Marks in use in Great Britain and Ireland between around 1830 and the 1870’s.  The cancels are categorized into four types, and listed according to type in regard to their use in English towns.  There are separate chapters on London, Scotland and Ireland.  Illustrated in black & white.