Hargreaves, J. & Co
Englische Uhrmacher
Literatur
The London Wholesale, Manufacturing and Retail Goldsmiths, Silversmiths, Jewellers, Watchmakers, Opticians and Cutlers Directory 1861, 1996 Facsimile pub J Wadson, ISBN 0-9528034-0-2
Alan Shenton, Pocket Watches 19th & 20th Century, Pub Antique Collectors Club 1996, ISBN 1-85149-211-9