Two infants with gastric duplications were treated by resection. One required the additional removal of ectopic spleen and pancreas. In both cases, the displacement of a portion of pancreatic tissue from the ventral anlage to a position anterior and cephalad to the duplication strongly favors the "neurenteric band" theory of embryogenesis.
Torma MJ. Of Double Stomachs. Arch Surg. 1974;109(4):555-557. doi:10.1001/archsurg.1974.01360040073019