Proportional representation proper uses a ranked choice of candidates, equitably elected with a proportional count, in multi-member constituencies. This single transferable vote transcends party divisions by allowing voters to make their own lists of candidates (not exclusive party lists) with or without respect to party lines. STV is free PR and STV is unitary or fraternal PR. 
There is none so blind as those who will not see.
Richard Lung. "Democracy Science" links 3 free e-books on election method.