@article {agarwal2004semipositone,
	title = {Semipositone higher-order differential equations},
	journal = {Applied Mathematics Letters},
	volume = {17},
	number = {2},
	year = {2004},
	note = {n/a},
	pages = {201{\textendash}208},
	publisher = {Oxford; New York: Pergamon Press, 1988-},
	abstract = {n/a},
	author = {Agarwal, Ravi P and Said R. Grace and O{\textquoteright}regan, Donal}
}
