I asked my friend Paul Goldfield who lives in Rome ( http://paulgoldfield.wordpress.com/author/paulgoldfield/ ) about Alfredo. So he asked some of the cooks around him and he sends me this one interpretation:
Grated Parmaggiano, grated Fontina, and a very small amount of Gorgonzola dolce.
The cheeses are melted separately then combined.
Then add cream (or butter)
Add a small amount of pasta water to combine the cream and cheeses together.
And here I thought I was going to put an end to the debate! :D :D