- Halliday and Hasan discuss different types of cohesive relationships in texts, including reference, substitution, ellipsis, and lexical relationships.
- There are three types of referential relationships: exophoric which don't contribute to cohesion, and endophoric relationships which are either anaphoric, looking back in the text, or cataphoric, looking forward.
- Cohesion is necessary but not sufficient for a text - a group of sentences can have some cohesive elements but not qualify as a coherent text without other linking features.