| 
                                            [1]
                                         | 
                                        
                                             E. Polak, G. Ribiere. Note sur la xonvergence de directions conjugees. Rev. Francaise informat Recherche Operatinelle 3e Annee, 1969, 16: 35-43. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [2]
                                         | 
                                        
                                             B. T. Polyak. The conjugate gradient method in extreme problems. USSR Comp Math Math Phys., 1969, 9(4): 94-112. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [3]
                                         | 
                                        
                                             R. Fletcher, C. Reeves. Function minimization by conjugate gradients. HHHHHComputer JournalHHHHH, 1964, 7(2): 149-154. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [4]
                                         | 
                                        
                                             R. Fletcher. Practical Method of Optimization. New York: John Wiley & Sons, 1998. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [5]
                                         | 
                                        
                                             Y. Liu, C. Storey. Efficient generalized conjugate gradient algorithms, part 1: theory. Journal of optimization theory and Application, 1992, 69(1):129-137. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [6]
                                         | 
                                        
                                             M. R. Hestenes, E. Stiefel. Method of conjugate gradient for solving linear equations. Res. Nat. Bur. Stand., 1952, 49(6): 409-436. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [7]
                                         | 
                                        
                                             Y. H. Dai, Y. Yuan. A nonlinear conjugate gradient method with a strong global convergence property. SIAM Journal on Optimization, 2000, 10(177): 177-182. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [8]
                                         | 
                                        
                                             Y. Dai, L. Z. Liao. New conjugacy conditions and related nonlinear 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [9]
                                         | 
                                        
                                             conjugate methods. Appl. Math. Optim., 2001, 43(1): 87-101. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [10]
                                         | 
                                        
                                             W. W. Hager, H. Zhang. A new conjugate gradient method with guaranteed descent and an efficient line search. SIAM Journal on Optimization, 2005, 16(1): 170-192. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [11]
                                         | 
                                        
                                             W. W. Hager, H. Zhang. Algorithm 851: CGDESENT, A conjugate gradient method with guaranteed descent. ACM Transactions on Mathematical Software, 2006, 32(1): 113-137. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [12]
                                         | 
                                        
                                             G. Li, C. Tang, Z. Wei. New conjugacy condition and related new conjugate gradient methods for unconstrained optimization problems. Journal of Computational and Applied Mathemathics, 2007, 202(2): 532-539. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [13]
                                         | 
                                        
                                             Z. Wei, G. Li, L. Qi. New nonlinear conjugate gradient formulas for large-scale unconstrained optimization problems. Applied Mathematics and Computation, 2006, 179(2): 407-430. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [14]
                                         | 
                                        
                                             Z. Wei, G. Li, L. Qi. Global convergence of the PRP conjugate gradient methods with inexact line search for nonconvex unconstrained optimization problems. Mathematics of Computation, 2008, 77(264): 2173-2193. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [15]
                                         | 
                                        
                                             Z. Wei, S. Yao, L. Lin. The convergence properties of some new conjugate gradient methods. Applied Mathematics and Computation, 2006, 183(2): 1341-1350. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [16]
                                         | 
                                        
                                             G. L. Yuan. Modified nonlinear conjugate gradient methods with suf-ficient descent property for large-scale optimization problems. Optimization Letters, 2009, 3(1): 11-21. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [17]
                                         | 
                                        
                                             G. L. Yuan, X. W. Lu. A modified PRP conjugate gradient method. Annals of Operations Research, 2009, 166(1): 73-90. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [18]
                                         | 
                                        
                                             G. L. Yuan, X. W. Lu, Z. X. Wei. A conjugate gradient method with descent direction for unconstrained optimization. Journal of Computational and Applied Mathematics, 2009, 233(2):519-530. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [19]
                                         | 
                                        
                                             L. Zhang, W. Zhou, D. Li. A descent modified Polak-Ribiere- Polyak conjugate method and its global convergence. IMA Journal on Numerical Analysis, 2006, 26(4): 629-649. 
                                         | 
                                    
                     
                                
                                    
                                        | 
                                            [20]
                                         | 
                                        
                                             J. C. Gilbert, J. Nocedal. Global Convergence properties of conjugate gradient methods for optimization. SIAM Journal on Optimization, 1992, 2(1): 21-42. 
                                         |