Kidd, A. (1994). The marks are on the knowledge worker. In CHI '94: Proceedings of the SIGCHI conference on Human factors in computing systems, pages 186-191, New York, NY, USA. ACM Press:
"Knowledge workers do not carry much written information with them when they travel and rarely consult their filed information when working in their offices. Their desks are cluttered and seemingly function as a spatial holding pattern for current inputs and ideas." 
"It seems that knowledge workers use physical space, such as desks or floors, as a temporary holding pattern for inputs and ideas which they cannot yet categorise or even decide how they might use (...)" [p. 187]
Most of what the author talks, back in 1994, reasons with my own observations, namely what concerns clutter desks, use of floor space and sense of order out of (apparent) disorder corresponds with the descriptions and transcripts of what was observed 15 years ago.