@article {MyersUSM91,
	title = {Fock{\textquoteright}s expansion, {K}ato{\textquoteright}s cusp conditions, and the exponential ansatz},
	journal = {Physical Review A},
	volume = {44},
	year = {1991},
	pages = {5537-5546},
	author = {Myers, C. R. and Umrigar, C. J. and Sethna, J. P. and Morgan, J. D.}
}
