Harry was a specialist in the stamps and postal history of the Anglo-Boer War and the Rhodesias. His Rhodesian collection was sold by Christie's Robson Lowe in 1986.
The pseudo-siege of Schweizer-Reneke, Philatelic Federation of South Africa, 2005. (With John Groenewald) ISBN0620334916
The riddle of Rustenburg, Philatelic Federation of South Africa, 2007. (With John Groenewald) ISBN0620370092
The legacy of Lydenburg, Philatelic Federation of South Africa, 2009. (With John Groenewald) ISBN0620416882
References
^"Harry Birkhead" by Joh Groenwald in The Anglo-Boer War, 1899-1902 Featuring Occupation and Siege Issues The Harry Birkhead Collection. Spink, London, 2014. p. 3.
^RDPSA, Philatelic Federation of South Africa, 2013. Retrieved 8 April 2013. Archived here.