Rittel, H.
, and
M. Webber
(1973)
`Dilemmas in a General Theory of Planning'
, Policy Sciences Vol. 4, pp.
155—69
.
Amsterdam: Elsevier Scientific Publishing
Company, Inc
. URL (accessed February 2007): http://www.stanford.edu/~rhorn/a/recent/spchKnwldgPACKARD.pdf