Explicit Structure in Print and On-Screen Documents
http://www.leaonline.com/doi/abs/10.1207/s15427625tcq1401_3
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  peer-reviewed

Farkas, David K.
Technical Communication Quarterly
2005

Abstract:

The structure of print and on-screen documents is made explicit through headings and links. Three important concepts for understanding explicit structure are (1) the display-unit properties of each document medium, (2) the flexible relationship between explicit and implicit structure, and (3) the distinction between populated and unpopulated locations in a hierarchy. These concepts help us better understand standard print documents, structured writing, websites, help systems, and PowerPoint, as well as the potential effects of content management systems on how documents are created.