@article{NUMA_1965__7_131655,
     author = {H.P. K\"UNZI and H. TZSCHACH},
     title = {The {Duoplex-Algorithm.}},
     journal = {Numerische Mathematik},
     pages = {222--225},
     publisher = {mathdoc},
     volume = {7},
     year = {1965},
     zbl = {0132.13803},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1965__7_131655/}
}