For PSAI: (a) China, on https://politicalreform.ie and (b) https://politicalreform.ie/2019/10/15/decisions-decisions-binary-or-multi-option-and-or-preferential-votes-by-peter-emerson-director-de-borda-institute/
For the RSA: (c) https://www.thersa.org/discover/publications-and-articles/rsa-blogs/2019/11/general-election-binary/