Z Daoxiang, P Yan - Applied Mathematics Letters, 2017 - Elsevier
This paper investigates the uniqueness and hyperbolicity of the autonomous planar system
with zero diagonal coefficient x ̇= p 2 (y) q 2 (x) y, y ̇= p 3 (y) q 3 (x) x+ p 4 (y) q 4 (x) y and …