Conformal Euler-Lagrangian Equations on Para-Quaternionic Kahler   Manifolds
  This manuscript presents an attempt to introduce Lagrangian formalism for mechanical systems using para-quaternionic Kahler manifolds, which represent an interesting multidisciplinary field of research. In addition to, the geometrical-physical results related to para-quaternionic Kahler mechanical systems are also given. 
Zeki Kasap and Mehmet Tekkoyun
math.GM