@article {zigler1987point,
	title = {Point radiographic source characterization},
	journal = {Journal of applied physics},
	volume = {62},
	number = {5},
	year = {1987},
	pages = {1671{\textendash}1674},
	publisher = {American Institute of Physics},
	author = {Zigler, A and Lee, RW and Kilkenny, JD and Kolbe, G and Nathel, H}
}
