Voir la notice de l'article provenant de la source The Polish Digital Mathematics Library
@article{CC_2007_36_3_a20, author = {Zaj{\'\i}\v{c}ek, Lud\v{e}k}, title = {A {C1} function which is nowhere strongly paraconvex and nowhere semiconcave}, journal = {Control and Cybernetics}, pages = {803--810}, publisher = {mathdoc}, volume = {36}, number = {3}, year = {2007}, zbl = {1173.26309}, language = {en}, url = {http://geodesic.mathdoc.fr/item/CC_2007_36_3_a20/} }
Zajíček, Luděk. A C1 function which is nowhere strongly paraconvex and nowhere semiconcave. Control and Cybernetics, Tome 36 (2007) no. 3, pp. 803-810. http://geodesic.mathdoc.fr/item/CC_2007_36_3_a20/