@misc{O._Engel_The,
 author={O. Engel and Á. O. Páll-Szabó},
 address={Երևան},
 howpublished={online},
 publisher={Հայաստանի ԳԱԱ},
 title={The radius of convexity of particular functions and applications to the study of second order differential inequality},
 type={Հոդված},
 keywords={Mathematics, Science, Geometry; Trigonometry; Topology},
}