The Samuel Leibowitz Papers are part of the Benson Latin American Collection at The University of Texas at Austin.
From the website:
"Yiddish author Samuel Leibowitz was born in Panevezys, Lithuania in 1912 and died in Johannesburg, South Africa, on June 16, 1976. He emigrated to the Johannesburg, South Africa, area in 1929. He began publishing in 1931 in Yiddish newspapers and journals in South Africa. Most of his work remains unpublished."