I want to use a particular short quote in my Hotmail sig line, & maybe for the SDMB, too. However , I cannot bring myself to use a quote without attributing it to it’s correct source. [sub]Those are my pretentions to intellectual ethics showing, as opposed to my unethical intellectual pretentions.[/sub] 
Who said this:
It was either Dr. Hunter S. Thompson, outlaw Gonzo journalist; Leo Tolstoy, Russian novelist; or some Brazilian guy. 
Any ideas?
My first idea is to ask you where you got the quote?
Assuming that we have only the three choices you propose, I would chose Tolstoi, as he used the Mazurka in Anna Karenina.
But the quote as you propose it doesn’t sound like Tolstoi.
It sounds like Hunter S Thompson, but google isn’t coming up with anything and I don’t have time to go through my copies of his books right now. 
… I’ll note the following:
[ul]
[li] The mazurka is a Polish folk dance.[/li][li] Two prominent Latin American writers are Pablo Neruda and Gabriel Garcia Marquez.[/li][li] Forgive me, Opal, for I have sinned*.[/li][/ul]
[sub]*Everybody see this? Lists of only 2 items get an Opal mention, lists of 3+ items don’t need it! Thank you.[/sub]
Uhh… Lech Walesa?
The only thing that makes any sense to me.
Well, actually, what popped into my head was “Gomez Addams”, but then I realized that it’s the mamushka, not the mazurka, so never mind.
You could just say ‘author unknown’