This view is supported by an (as yet
unpublished) detailed investigation of Einstein’s theory of distant
parallelism by T. Sauer which I received 6 month after after
having submitted this review [288]. Sauer uses unpublished
correspondence in the Einstein Papers Archive, and points to “some
historical and systematic similarities between the Fernparallelismus episode and the Entwurf theory, i.e., the precurser theory of general
relativity theory pursued by Einstein in the years
1912-1915.”