@article{NUMA_1987__55_4_133349,
     author = {C.T. Kelley and E.W. Sachs},
     title = {A {Pointwise} {Quasi-Newton} {Method} for {Unconstrained} {Optimal} {Control} {Problems.}},
     journal = {Numerische Mathematik},
     pages = {159--176},
     publisher = {mathdoc},
     volume = {55},
     number = {4},
     year = {1987},
     zbl = {0649.65039},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1987__55_4_133349/}
}