DICOM PS3.3 2024b - Information Object Definitions
C.8.8.21.3 Definition Source Sequence

The Definition Source Sequence (0008,1156) may reference SOP Instances of Second Generation Radiotherapy IODs containing the same clinical content as the current Item.

Permitted SOP Classes in this Sequence shall contain the following Module:

DICOM PS3.3 2024b - Information Object Definitions