2004-12-06 [2023-01-12]. (原始内容存档于2023-01-12). Shiing-Shen Chern. A Simple Intrinsic Proof of the Gauss-Bonnet Formula for Closed Riemannian Manifolds. Annals
[2021-08-04]. ISBN 0 471 10409 4. (原始内容存档 (PDF)于2021-08-04) (英语). The main intrinsic factors are the design strength, the elastic modulus of aggregate, the