Heading, J. (1962). An introduction to phase-integral methods. Methuen.
Dyfyniad Arddull ChicagoHeading, John. An Introduction to Phase-integral Methods. London: Methuen, 1962.
Dyfyniad MLAHeading, John. An Introduction to Phase-integral Methods. Methuen, 1962.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.