Franklin

MLA

Schumpeter, Joseph A., Ulrich Hedtke, and Richard Swedberg. Briefe = Letters. .

APA

Schumpeter, J. A., Hedtke, U., & Swedberg, R. Briefe = Letters. .

Chicago

Schumpeter, Joseph A., Ulrich Hedtke, and Richard Swedberg. Briefe = Letters.