@article{MM2_1982__37_154828,
     author = {Lech Drewnowski},
     title = {A {Solution} to a {Problem} of de {Wilde} and {Tsirulnikov.}},
     journal = {Manuscripta mathematica},
     pages = {61--64},
     publisher = {mathdoc},
     volume = {37},
     year = {1982},
     zbl = {0486.46003},
     url = {http://geodesic.mathdoc.fr/item/MM2_1982__37_154828/}
}