Where are error and exception routines shown on DFDs?

1. When do we have a choice as to what will be included in a context diagram?
2. Which activities can be included in the logical processes on a logical DFD?
3. What are the guidelines for grouping logical activities for a logical DFD?
4. Where are error and exception routines shown on DFDs?
5. Where are error and exception routines shown on systems flowcharts?