Can anyone provide me with the reference for the following fact
(idea of the proof will be appreciated too):


Cohomology ring with $\mathbb Q$-coefficients of a group $G$ (I don't know precisely what the assumptions are: reductive complex algebraic group or maybe complex Lie group G with some restrictions. The cases I'm interested in are $GL\_n(\mathbb C)$ and $SL\_n(\mathbb C)$) is the exterior algebra on the generators of odd degrees, with the number of generators equal to the rank of $G$.


This fact is attributed to H.Hopf, but I wasn't able to find a reference. 


Thanks.



Cohomology rings of $ GL_n(C)$, $SL_n(C)$
If $G$ is a connected Lie group (or just a connected loop space with finite homology) then $H^\*(G,\mathbf{Q})$ is a Hopf algebra. Graded connected Hopf algebras over $\mathbf{Q}$ are always tensor products of exterior algebras in odd degrees with polynomial algebras in even degrees. Since polynomial algebras are infinite, they can't occur. The reference to Hopf is probably H. Hopf, Über die algebraische Anzahl von Fixpunkten, Math. Z. 29 (1929), 493–524. For the classification of Hopf algebras, see also A. Borel, Sur la cohomologie des espaces fibrés principaux et des espaces homogènes de
groupes de Lie compacts, Ann. of Math. (2) 57 (1953), 115–207.


