  Recent outer bounds on the capacity region of Gaussian interference channels
are generalized to $m$-user channels with $m>2$ and asymmetric powers and
crosstalk coefficients. The bounds are again shown to give the sum-rate
capacity for Gaussian interference channels with low powers and crosstalk
coefficients. The capacity is achieved by using single-user detection at each
receiver, i.e., treating the interference as noise incurs no loss in
performance.
