Czarnecki, Sławomir, and Tomasz Lewiński. “Shaping the Stiffest Three-Dimensional Structures from Two Given Isotropic Materials”. Computer Assisted Methods in Engineering and Science 13, no. 1 (March 31, 2006): 53–83. Accessed February 23, 2026. https://cames.ippt.pan.pl/index.php/cames/article/view/964.