Author: Brockelmann, C
Publisher:E J Brill, Leiden
Copyright:1938
Author: Widengren, Geo
Publisher:
Copyright:1938
Author: Vessberg, Olof
Publisher:C.W.K. Gleerup, Lund
Copyright:1941
Author: Markwart, Josef
Publisher:E. J. Brill, Leiden
Copyright:1938