I am looking for a reader-friendly proof of the following theorem:
let $A$ be a special $\Gamma$-space then $\pi_0(A(S^0))$ is a commutative monoid (I have proved up to this), if further it is an abelian group then the adjoint map $t: A(S^0) \to \Omega{BA(S^0)}$ for the structure map $s: \Sigma(A(S^0)) \to BA(S^0)$ is a weak homotopy equivalence
Dan Freed in his notes theorem 19.41 points to Segal's paper as reference but I cannot find a proof there (did I miss it?).