Andrews, B. The ricci flow in riemannian geometry [Electronic resource] : a complete proof of the differentiable 1/4-pinching sphere theorem / B. Andrews, C. Hopper. - Electronic text data. - Berlin ; Heidelberg : Springer-Verlag, 2011. - (Lecture notes in mathematics, ISSN 0075-8434 ; 2011). - ISBN 978-3-642-16286-2 : Б. ц.