@article {agarwal2007oscillation,
	title = {Oscillation of fourth order nonlinear difference equations},
	journal = {Int. J. Difference Equ},
	volume = {2},
	number = {2},
	year = {2007},
	note = {n/a},
	pages = {123{\textendash}137},
	abstract = {n/a},
	author = {Agarwal, Ravi P and Said R. Grace and Wong, Patricia JY}
}
