John Archibald Wheeler
Other non-traversable wormholes include "Lorentzian wormholes" (first proposed by John Archibald Wheeler in 1957), wormholes creating a spacetime foam in a general relativistic spacetime manifold depicted by a Lorentzian manifold, and "Euclidean wormholes" (named after Euclidean manifold, a structure of Riemannian manifold).