| [1] | Hale J K.Ordinary Differential Equations[M].New York:Wiley Interscience,1969. | 
		
				| [2] | Nagle R K.Nonlinear boundary value problems for ordinary differential equations with a small parameter[J].SIAM J Math Analysis,1978,9(3):719-729. | 
		
				| [3] | Mawhin J.Landesman-Lazter.stype problems for nonlinear equations[A].In:Conferenze Seminario Matematica[M].DiBari:Dell Universita,1977,147. | 
		
				| [4] | Fucik S.Solva bility of Nonlinear Equations and Boundary Value Problems[M].Dordrecht,Holland:D.Reidel Publishing,1980. | 
		
				| [5] | Nagle R K,Sinkala Z.Existence of 2π-periodic solutions for nonlinear systems of first-order ordinary differential equations at resonance[J].Nonlinear Analysis(TMA),1995,25(1):1-16. | 
		
				| [6] | MA Shi-wang,WANG Zhi-cheng,YU Jian-she.Coincidence degree and periodic solutions of Duffing equations[J].Nonlin ear Analysis(TMA),1998,34(2):443-460. | 
		
				| [7] | Lazer A C,Leach D E.Bounded perturbations of forced harmonic oscillations at resonance[J],Ann Mat Pura Appl,1969,82(1):49-68. | 
		
				| [8] | Schuur J D.Perturbation at resonance for a fourth order ordinary differential equation[J].J Math Anal Appl,1978,65(1):20-25. | 
		
				| [9] | 丁同仁.共振点的非线性振动[J].中国科学(A辑),1982,(1):1-13. | 
		
				| [10] | HAO Dun-yuan,MA Shi-wang.Semilinear Duffing equations crossing resonance points[J].J Differential Equations,1997,133(1):98-116. | 
		
				| [11] | Mawhin J.Equivalence theorems for nonlinear operator equations and coincidence degree theory for some mapping in locally convex topological vector spaces[J].J Differential Equations,1972,12(2):610-636. | 
		
				| [12] | Mawhin J.Topolo gical Degree Methods in Nonlinear Boundary Value Problems CBMS[M].Providence RI:Amer Math Soc,1979,40. | 
		
				| [13] | Deimling K.N onlinear Functional Analysis[M].New York:Springer-Verlag,1985. |