Hughes, D. R., & Piper, F. C. (1985). Design theory. Cambridge University Press.
Dyfyniad Arddull ChicagoHughes, D. R., and F. C. Piper. Design Theory. Cambridge, London: Cambridge University Press, 1985.
Dyfyniad MLAHughes, D. R., and F. C. Piper. Design Theory. Cambridge University Press, 1985.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.