1. G. Rawitscher, Solution to a linear equation for the phase amplitude description of a wave-function, submitted to J. Phys. B
2. W.E. Milne, Phys. Rev. 35, 863 (1930)
3. The authors thank Professor Gerald Dunne, from the Department of Physics at UCONN, for calling their attention to the existence of this equation
4. H. Jeffreys, B.S. Jeffreys, Methods of Mathematical Physics (Cambridge University Press, Cambridge, 1966)
5. H.A. Kramers, Z. Phys. 39, 828 (1926)