@article { bilbaoandsmithacustica05,
	title = {Energy-conserving Finite Difference Schemes for Nonlinear Strings},
	journal = {Acustica{\textendash}-Acta Acustica},
	volume = {91(2)},
	year = {2005},
	pages = {299{\textendash}311},
	author = {Stefan Bilbao and Julius O. Smith}
}
