The penultimate part of Journal entries relating to Hasmonean are here.
As well as his personal Journal, unpublished autobiography and Yiddish book, he also had two significant translations published. These are two sites which a quick and unacademic Google search brings up:
God’s Wilderness Discoveries in Sinai
Beno Rothenberg ; in collaboration with Yohanan Aharoni and Avia Hashimshoni ; [translated from the Hebrew by Joseph Witriol].
Heinrich Heine : the artist in revolt / by M.Brod. Trans. from the German by J.Witriol
Serendipitously I spotted the latter book in a Magg’s catalogue of books for sale from Yehudi Menuhin’s library – see also here. It’s worth a look at their site – they are one of the most renowned antiquarian booksellers in the world.