Black, William Harman, 1868-. "The real Europe pocket guide book (from official sources) (number 12 of the pocket guides known as "Black's blue books") ... also a complete tour of Palestine and northern Egypt, with 24 outline maps, and comprehensive index, research and study references to volumes and pages of Encyclopaedia britannica; every question answered ... the only guide book covering all of Europe, with pre-war and post-war names of cities, by Harman Black." HathiTrust. 1927, http://hdl.handle.net/2027/mdp.39015063621125.

Black, William Harman, 1868- (1927). The real Europe pocket guide book (from official sources) (number 12 of the pocket guides known as "Black's blue books") ... also a complete tour of Palestine and northern Egypt, with 24 outline maps, and comprehensive index, research and study references to volumes and pages of Encyclopaedia britannica; every question answered ... the only guide book covering all of Europe, with pre-war and post-war names of cities, by Harman Black. Retrieved from http://hdl.handle.net/2027/mdp.39015063621125

Black, William Harman, 1868-. "The real Europe pocket guide book (from official sources) (number 12 of the pocket guides known as "Black's blue books") ... also a complete tour of Palestine and northern Egypt, with 24 outline maps, and comprehensive index, research and study references to volumes and pages of Encyclopaedia britannica; every question answered ... the only guide book covering all of Europe, with pre-war and post-war names of cities, by Harman Black." 1927. July 20, 2025. http://hdl.handle.net/2027/mdp.39015063621125.