"Leffers, Gustav"@en . "German flying ace" . "1895Z"^^ . "1916-12-27Z"^^ . . "Gustav Leffers (2 January 1895 \u201327 December 1916) was a German flying ace in World War I, credited with 9 victories."@en . . . "1895-01-02Z"^^ . "1914Z"^^ . "1916Z"^^ . . "German Empire" . . . . "Gustav Leffers"@en .