Ulmanu , Vlad, Dragos Zisopol, и Ciprian Trifan. 2007. Experimental Research Concerning the Influence of External Diameteron the Behavior of Coiled Tubing to Cyclic Bending With Internal Pressure. Записки Горного института 170 (2), 46-48. https://pmi.spmi.ru/pmi/article/view/7711.

Ulmanu , Vlad, Dragos Zisopol, and Ciprian Trifan. 2007. “Experimental Research Concerning the Influence of External Diameter on the Behavior of Coiled Tubing to Cyclic Bending With Internal Pressure”. Journal of Mining Institute 170 (2), 46-48. https://pmi.spmi.ru/pmi/article/view/7711.