In [this][1] paper, page $6$ the authors  state the following:

> By Weil’s theorem $[17]$, any local algebraic group is birationally
> equivalent to an algebraic group.

Where 

$[17]$ A.Weil. On algebraic groups of transformations. Amer. J. Math. 77, (1955), 355-391.

I would like to know if I can find that Theorem in a textbook about Algebraic Groups.

I would appreciate your help.

PS. I did ask this [question][2] in StackExchange, but I got no answer.


  [1]: http://www.math.u-szeged.hu/~nagyg/pub/grishkov_nagy3.pdf
  [2]: http://math.stackexchange.com/posts/123805/edit