1.
Bony J-M, Colombini F, Pernazza L. On square roots of class C<sup>m</sup> of nonnegative functions of one variable. Annali Scienze [Internet]. 2010Sep.28 [cited 2026Feb.20];9(3):635-44. Available from: https://journals.sns.it/index.php/annaliscienze/article/view/216