Geodesic
On Darboux points and the perfectly closed class of functions
Acta Universitatis Lodziensis. Folia Mathematica, Tome 04 (1991) 
Pawlak, Ryszard J. On Darboux points and the perfectly closed class of functions. Acta Universitatis Lodziensis. Folia Mathematica, Tome 04 (1991). http://geodesic.mathdoc.fr/item/AULFM_1991_04_a6/
@article{AULFM_1991_04_a6,
     author = {Pawlak, Ryszard J.},
     title = {On {Darboux} points and the perfectly closed class of functions},
     journal = {Acta Universitatis Lodziensis. Folia Mathematica},
     year = {1991},
     volume = {04},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AULFM_1991_04_a6/}
}
TY  - JOUR
AU  - Pawlak, Ryszard J.
TI  - On Darboux points and the perfectly closed class of functions
JO  - Acta Universitatis Lodziensis. Folia Mathematica
PY  - 1991
VL  - 04
UR  - http://geodesic.mathdoc.fr/item/AULFM_1991_04_a6/
LA  - en
ID  - AULFM_1991_04_a6
ER  - 
%0 Journal Article
%A Pawlak, Ryszard J.
%T On Darboux points and the perfectly closed class of functions
%J Acta Universitatis Lodziensis. Folia Mathematica
%D 1991
%V 04
%U http://geodesic.mathdoc.fr/item/AULFM_1991_04_a6/
%G en
%F AULFM_1991_04_a6

Voir la notice de l'article provenant de la source University of Lodz Repository

The present paper is intended to discuss problems connected with operations on Darboux functions at some point x0.