UML sequence diagram combined fragment is an interaction fragment which defines a combination (expression) of interaction fragments.
Sequence Diagrams | SAP Help Portal
High-Level Sequence Diagrams
UML Tutorial - Use Case, Activity, Class and Sequence Diagrams - Essential Software Modeling - YouTube
Concurrency in UML
Simple Sequence Diagram Template showing parallel processing activities. Click on the image to edit online and download as P… | Sequence diagram, Diagram, Templates
Tracking sequence diagram with parallel communication. | Download Scientific Diagram