APA

Contreras M. E., .The Bolivian Tin Mining Industry in the First Half of the Twentieth Century. [s.l.]: University of London.

Chicago

Contreras Manuel E, .The Bolivian Tin Mining Industry in the First Half of the Twentieth Century. [s.l.]: University of London.

Harvard

Contreras M. E., .The Bolivian Tin Mining Industry in the First Half of the Twentieth Century. [s.l.]: University of London.

MLA

Contreras Manuel E, .[s.l.]: University of London. .