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• [5] Walter Leighton, Comparison theorems for linear differential equations of second order, Proc. Amer. Math. Soc. 13 (1962), 603–610. MR 0140759, https://doi.org/10.1090/S0002-9939-1962-0140759-0
• [6] M. H. Protter, A comparison theorem for elliptic equations, Proc. Amer. Math. Soc. 10 (1959), 296–299. MR 0107076, https://doi.org/10.1090/S0002-9939-1959-0107076-6
• [7] C. A. Swanson, A comparison theorem for elliptic differential equations, Proc. Amer. Math. Soc. 17 (1966), 611–616. MR 0201781, https://doi.org/10.1090/S0002-9939-1966-0201781-2

Bibliography

[1]

N. Aronszajn, A unique continuation theorem for solutions of elliptic partial differential equations or inequalities of second order, J. Math. Pures Appl. 36 (1957), 235-249. MR 0092067 (19:1056c)

[2]

Colin Clark and C. A. Swanson, Comparison theorems for elliptic differential equations, Proc. Amer. Math. Soc. 16 (1965), 886-890. MR 0180753 (31:4983)

[3]

F. R. Gantmacher, The theory of matrices, Vol. I, Chelsea, New York, 1959.

[4]

Philip Hartman and Aurel Wintner, On a comparison theorem for self-adjoint partial differential equations of elliptic type, Proc. Amer. Math. Soc. 6 (1955), 862-865. MR 0074668 (17:627b)

[5]

Walter Leighton, Comparison theorems for linear differential equations of second order, Proc. Amer. Math. Soc. 13 (1962), 603-610. MR 0140759 (25:4173)

[6]

M. H. Protter, A comparison theorem for elliptic equations, Proc. Amer. Math. Soc. 10 (1959), 296-299. MR 0107076 (21:5803)

[7]

C. A. Swanson, A comparison theorem for elliptic differential equations, Proc. Amer. Math. Soc. 17 (1966), 611-616. MR 0201781 (34:1663)