[1] I. Bihary: Zeros of the Böcher - function and its derivative with respect to differential equation $y" + p(x) y = 0$ II. (to appear).

[2] O. Borůvka: Linear Differential Transformations of the Second Order. The English Univ. Press, (1971) London. MR 0463539

[3] Z. Došlá: Monotonicity properties of the linear combination of derivatives of some special functions. (to appear). Arch. Math. (Brno), 21, (1985), 147 - 157. MR 0833125

[4] A. Erdélyi, al: Higher transcendental functions. vol. 2, Mc Graw-Hill, New York, 1954.

[5] M. Háčik: Generalization of amplitude, phase and accompanying differential equations. Acta Univ. Palackianae Olomucensis, FRN, 33, (1971), 7-17. MR 0352583

[6] J. Heading: Consistency invariants and transformations between second order linear differential equations. Preprint.

[7] M. Laitoch: L'équation associée dans la théorie des transformations des équations différentielles du second ordre. Acta Univ. Palackianae Olomucensis, 12, 0963), 45 - 62. MR 0276527 | Zbl 0256.34005

[8] M. Muldoon: On the zeros of a function related to Bessel functions. Arch. Math. (Brno), 18, (1982), 22-34. MR 0683343 | Zbl 0504.33005

[9] S. Staněk: On a certain transformation of the solution of two second order differential equations. Acta Univ. Palackianae Olomucensis, FRN, 76, math. XXII, (1983), 81-90. MR 0744702

[10] J. Vosmanský: The monotonicity of extremants of integrals of the differential equation y'' + q(t)y = 0. Arch. Math. (Brno), 2, (1966), 105-111. MR 0216072 | Zbl 0219.34035

[11] J. Vosmanský: Certain higher monotonicity properties of i-th derivatives of solutions of y'' + a(t) y' + b(t) y = 0. Arch. Math. (Brno), X, (1974), 87-102. MR 0399578