Stamp perforation : the Somerset House years, 1848 to 1880, including an illustrated guide to perforation varieties /
Simpson, Ray C.
Sargent, Peter J.
Royal Philatelic Society (Great Britain)
London : Royal Philatelic Society London,
2006.
Includes bibliographical references and index.
Somerset House (London, England)
Perforations (Philately)
Postage stamps