Taylor, L. "The Susa wreath group Alexanders: The first step in the transformation of an anchor seal to a dynastic emblem" in Koinon II (2019), p. 63 - 82.

A ; tetradrachm  die  study  of  the  Susa  wreath  group  (Susa  Group  5)  of  Alexanders  (Price  3853-60)  attributed  to  the  satrapy  of  Aspeisas  in  the  period  316/5-312/1  BC,  indicates  that  the  coinage  should be downdated to the period 311/0-309/8 BC, the earliest coinage of Seleukos from the mint. A newly identified component of the coinage, die linked to the wreath group while bearing an anchor recut over the wreath, represents the first appearance on coinage of what was to become the  primary Seleukid dynastic emblem.  It  sheds  light  on  the  origin  and  timing  of  placement  of  Seleukos' personal insignia, or seal, on his coinage, and its subsequent development into a dynastic emblem.