Enquanto traduzindo o seguinte trecho da página sobre a União Soviética, me perguntei como poderia ser traduzido o "SFSR", visto que nunca vi nenhuma bibliografia em português utilizando alguma sigla como esta ou com algum significado parecido.
"It was established in 1922 as a union of four socialist republics created after the 1917 October Revolution, namely the Russian SFSR, the Transcaucasian SFSR, the Ukrainian SSR and Byelorussian SSR. The years that followed saw the addition of the Uzbek and Tajik SSRs; the Transcaucasian SFSR was dissolved in 1936 in favor of the elevated SSRs of Georgia, Armenia and Azerbaijan. From 1956 to 1991, the union comprised 15 member republics, two of which had their own member seats at the United Nations."