D. O. Blood & Co.
Carriers in Philadelphia, USA. Issued stamps for local use between 1841 and circa 1860.
Source
Sutton 1966, pp. 41, 231.
Bibliography
Sutton, R. J. 1966. The stamp collector’s encyclopaedia. 7th edition. 6th edition revised by K. W. Anthony. London: Stanley Paul. [Vols. 10,11]
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