Parkinson, N. C. (1966). A law unto themselves. John murray.
Dyfyniad Arddull ChicagoParkinson, Northcote C. A Law Unto Themselves. London: John murray, 1966.
Dyfyniad MLAParkinson, Northcote C. A Law Unto Themselves. John murray, 1966.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.