Wormholes in vacuum Brans-Dicke theory
  It is shown that among the different classes of claimed static wormhole solutions of the vacuum Brans-Dicke theory only Brans Class I solution with coupling constant $\omega$ less than -1.5 (excluding the point $\omega =2$) gives rise to physically viable traversable wormhole geometry. Usability of this wormhole geometry for interstellar travel has been examined. 
Arunava Bhadra and Kabita Sarkar