On the intersection of groups of dispersions of the equation and of its accompanying equation
On the intersection of groups of increasing dispersions in two second order oscillatory differential equations
On the intersection of the set of solutions of two Kummer's differential equations
On the isospectral beams.
On the -boundedness of solutions for products of quasi-integro differential equations.
On the -solutions to general second-order nonsymmetric differential equations.
On the limit cycle of the Liénard equation
In the paper, we give an existence theorem of periodic solution for Liénard equation , . As a result, we estimate the amplitude (maximal -value) of the limit cycle of the van der Pol equation , from above by for every . The result is an improvement of the author’s previous estimation .
On the limit cycle of the van der Pol equation
On the Limit Point Classification of Second Order Differential Equations.
On the Limit-Point and Strong Limit-Point Classification of 2 n-th Order Differential Expressions with Widly Oscillating Coefficients.
On the linearization of second-order differential and difference equations.
On the Liouville-type transformation for differential systems
On the Location of Zeros of Solutions of f'' + A(z)f = 0 where A(z) is Entire.
On the location of zeros of solutions of non-homogeneous linear differential equations
On the method of Esclangon
On the monotonicity of nonnegative solutions and the uniqueness of eigenvalues
On the monotonicity of the period function of some second order equations
On the monotonicity of the quotient of certain abelian integrals.
On the Nonoscillatory Properties of Solutions of a Functional Differential Equation
On the n-th order iterative ordinary linear differential equations.