We prove a version of the real Koebe principle for interval (or circle) maps with non-flat critical points.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm185-1-4, author = {Weixiao Shen and Michael Todd}, title = {Real $C^k$ Koebe principle}, journal = {Fundamenta Mathematicae}, volume = {185}, year = {2005}, pages = {61-69}, zbl = {1088.37016}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm185-1-4} }
Weixiao Shen; Michael Todd. Real $C^k$ Koebe principle. Fundamenta Mathematicae, Tome 185 (2005) pp. 61-69. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm185-1-4/