R. N. P. Hawkins
A dictionary of makers
Four studies of Britishmetallic tickets and commercial checks of the 19th-20th centuries
Guide list of public houses and beer shops and their proprietors featured on metallic checks issued within 1830-1910 in Birmingham and Smethwick
Supplement III to catalogue of the advertisement imitations of 'spade' guineas and their halves (BNJ 32 (1963), 34(1965), and 37 (1968)