Ismail, Bahija Khalil and Tosi, Maurizio (1976):

Ismail, Bahija Khalil - Tosi, Maurizio, A Turquoise Neck-Stone of King Ninurta-apal-ekur: Sumer 32 (1976, ersch. 1977) 105-112, 4 fig. [IM 56801, inscribed MA “neck-stone” (NA4.GU)]; in Arabic: ibid. 81-87.