His book The South Slav Question is a work on the South Slav geopolitical issues .
Ivo Pilar ( 19 June 1874 -- 3 September 1933 ) was a Croatian historian , politician and lawyer .
Ivo Pilar 's book The South Slav Question is a work on the South Slav geopolitical issues .
Ivo Pilar ( 19 June 1874 -- 3 September 1933 ) was a Croatian historian , politician and lawyer .