@article{ZhuByrdLuNoce97,
 author         = {C. Zhu and R. H. Byrd and P. Lu and J. Nocedal},
 title          = {Algorithm 78: {L-BFGS-B}: Fortran subroutines for
                   large-scale bound constrained optimization},
 journal        = TOMS,
 volume         = 23, number = 4, pages = {550--560}, year = 1997}