  By a combination of analytical and numerical techniques, we demonstrate the
existence of spherical, asymptotically flat traversable wormholes supported by
exotic matter whose stress tensor relative to the orthonormal frame of Killing
observers takes the form of a perfect fluid possessing anisotropic pressures
and subject to linear equations of state: $\tau=\lambda\rho c^{2}$, $P=\mu\rho
c^{2}$. We show that there exists a four parameter family of asymptotically
flat spherical wormholes parametrized by the area of the throat A(0), the
gradient $\Lambda(0)$ of the red shift factor evaluated at the throat as well
as the values of $(\lambda, \mu)$. The latter are subject to restrictions:
$\lambda>1$ and $2\mu>\lambda$ or $\lambda<0$ and $2\mu<-|\lambda|$. For
particular values of $(\lambda, \mu)$, the stress tensor may be interpreted as
representing a phantom configuration, while for other values represents exotic
matter. All solutions have the property that the two asymptotically flat ends
posses finite ADM mass.
