“…One can see in the references of the paper some useful applications of FDEs in viscoelasticity, bioengineering, damping laws, rheology, thermodynamics, synchronization, dynamical system, electrical circuits, signal processing, and fluid mechanics, see. [1][2][3][4][5][6][7][8][9][10][11][12][13] The fractional order Klein-Gordon equation (KGE) is derived from the KGE of the integer order by switching time derivative by noninteger order ( ∈ [0, 1]) derivative. The fractional order KGE can be illustrated as below:…”