It´s parties that choose electoral systems (or Duverger´s Laws Upside Down).

MLA

Colomer, Josep M. It´s Parties That Choose Electoral Systems (or Duverger´s Laws Upside Down). s.l, 2003.

APA

Colomer, J. M. (2003). It´s parties that choose electoral systems (or Duverger´s Laws Upside Down). s.l.

Chicago

Colomer, Josep M. It´s Parties That Choose Electoral Systems (or Duverger´s Laws Upside Down). s.l., 2003.