[1] Vasil’eva A B, Butuzov V F, Kalachev L V. The boundary function method for singular perturbation problems. Philadelphia: SIAM, 1995

[2] Vasil’eva A B, Butuzov V F. Asymptotic expansions of solutions of singularly perturbed equations. Moscow: Nauka, 1973

[3] Farrel P A, Miller J J H, O’Riordan E, et al. Singularly perturbed differential equations with discontinuous source terms//Vulkov L G, Miller J J H. Analytical and Numerical Methods for Convection-Dominated and Singularly Perturbed Problems. New York: Nova Science Publishers, Inc, 2000: 23–32

[4] Howes F A. The asymptotic solution of a class of third-order boundary value problems arising in the theory of thin film flows. SIAM J Appl Math, 1983, 43(5):993–1004

[5] Horn R A, Johson C R. Topics in Matrix Analysis. Cambridge: Cambridge University Press, 1991

[6] Esipova V A. Asymptotic properties of general boundary value problems for singularly perturbed condi-tionally stable systems of ordinary differential equations. Differential Equations, 1975, 11(11): 1457–1465