“…For good references of CG methods with significant findings, please refer to Hager and Zhang [28], Sun and Zhang [11], Birgin and Martinez [3], Dai and Yuan [33], Yuan and Wei [6], Andrei [23], Shi and Guo [37], and Wei et al [39]. For a good compilation and comparative study of newer CG methods, please refer to Andrei [22,24] and Rivaie et al [18]. For a good explanation of classical CG method, please refer to Dai [29].…”