Dating these texts has long been a crux interpretum for modern scholars. Given the importance and persistence of this issue, there follows a chronological discussion of the letters allocated to the reigns of Esarhaddon and Assurbanipal. The letters of uncertain date contain much of interest but, as they cannot be allocated to any particular reign, they are not included in the following discussion.
Frances Reynolds
Frances Reynolds, 'Dating the Letters', The Babylonian Correspondence of Esarhaddon and Letters to Assurbanipal and Sin-šarru-iškun from Northern and Central Babylonia, SAA 18. Original publication: Helsinki, Helsinki University Press, 2003; online contents: SAAo/SAA18 Project, a sub-project of MOCCI, 2020 [http://oracc.org/saao/saa18/babyloniancorrespondence/datingtheletters/]