Electoral system for national legislature

Reforming Electoral Systems in Mexico, Horcasitas and Weldon, in Shugart and Wattenberg, Mixed Member Electoral Systems, OUP 2001, pp209-230 (esp table pp228-229)

Three exceptions to pure parallel system: a party with less than 60% of the vote cannot win more than 300 seats; a party with between 60% and 63% wins the number of seats to which it is proportionally entitled, making the system MMP for this party within this range; and no party can win more than 315 (63%) of the seats.

300 FPTP: 200 List PR using closed list and largest remainder