Cita APA (7a ed.)

Boelsche, W. (1909). Hackel, his life and work. Watts & Co..

Cita Chicago Style (17a ed.)

Boelsche, Wilhelm. Hackel, His Life and Work. London: Watts & Co., 1909.

Cita MLA (8a ed.)

Boelsche, Wilhelm. Hackel, His Life and Work. Watts & Co., 1909.