In this 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 some book about Algebraic Groups.
I would appreciate your help.
N.B.: I asked this also on MO.