Issues in the Design of Computer Support for Co-Authoring and Commenting 
This paper reports on a project to develop a “work in preparation” editor, or PREP editor, to study co-authoring and commenting relationships. As part of the project, we have identified three issues in designing computer support for co-authoring and commenting: (1) support for social interaction among co-authors and commenters; (2) support for cognitive aspects of co-authoring and external commenting; and (3) support for practicality in both types of interaction. For each of these issues, the paper describes the approach the PREP editor takes to address them.
Neuwirth, Christine M., David S. Kaufer, Ravinder Chandhok and James H. Morris. ACM SIGGROUP (1990). Design>Software>Collaboration