1. Parametric Stability of a Pendulum with Variable Length in an Elliptic Orbit

   • José Laudelino de Menezes Neto
   • Hildeberto E. Cabral

   OriginalPaper 30 July 2020 Pages: 323 - 329

   

2. On the Stability of Potential Systems under the Action of Non-conservative Positional Forces

   • Ranislav M. Bulatovic

   OriginalPaper 25 January 2021 Pages: 330 - 337

3. Optical Dromions and Domain Walls with the Kundu – Mukherjee – Naskar Equation by the Laplace – Adomian Decomposition Scheme

   • Oswaldo González-Gaxiola
   • Anjan Biswas
   • Abdullah Kamis Alzahrani

   OriginalPaper 30 July 2020 Pages: 338 - 348

   

4. Bernoulli Property for Some Hyperbolic Billiards

   • Rodrigo M.D. Andrade

   OriginalPaper 30 July 2020 Pages: 349 - 382

   

5. A New \((3+1)\)-dimensional Hirota Bilinear Equation: Its Bäcklund Transformation and Rational-type Solutions

   • Kamyar Hosseini
   • Majid Samavat
   • Zakia Hammouch

   OriginalPaper 30 July 2020 Pages: 383 - 391

   

6. Two Nonholonomic Chaotic Systems. Part II. On the Rolling of a Nonholonomic Bundle of Two Bodies

   • Alexey V. Borisov
   • Evgeniya A. Mikishanina

   OriginalPaper 30 July 2020 Pages: 392 - 400

   

7. The Method of Averaging for the Kapitza – Whitney Pendulum

   • Ivan Yu. Polekhin

   OriginalPaper 30 July 2020 Pages: 401 - 410