http://bernie.house.gov/pc/members.asp
Note that it's on Bernie Sanders' web page. Bernie is an avowed socialist.
Yes, it can be shown beyond a doubt that Pelosi is a member of the Progressive Caucus. What I want is irrefutable printed evidence that membership in the Progressive Caucus is the same as membership in the Democratic Socialists of America, or that the Progressive Caucus is a part of the DSA, and thus that Pelosi can irrefutably be called a Socialist.
(To me, anyone who wants to notably increase the portion of GDP controlled by the government, especially from its current 35% level to beyond the 50% level, is by definition a socialist, but most people think you're wearing a tinfoil hat if you call a "progressive" Democrat a socialist.)