@Article{LivierisPintelas12,
 AUTHOR    = {I.E. Livieris and P. Pintelas},
 Title     = {Globally convergent modified {P}erry conjugate gradient method},
 Journal   = {Applied Mathematics and Computation},
 Volume    = {218},
 Number    = {18},
 Pages     = {9197--9207},
 Year      = {2012}
}