@article {boscaggin2012one,
	title = {One-signed harmonic solutions and sign-changing subharmonic solutions to scalar second order differential equations},
	journal = {Advanced Nonlinear Studies},
	volume = {12},
	number = {3},
	year = {2012},
	pages = {445{\textendash}463},
	publisher = {Advanced Nonlinear Studies, Inc.},
	doi = {10.1515/ans-2012-0302},
	author = {Alberto Boscaggin}
}
