Stein, E.
(2017).
 Milestones of Direct Variational Calculus and its Analysis from the 17th Century until today and beyond – Mathematics meets Mechanics – with restriction to linear elasticity.
<em>Computer Assisted Methods In Engineering And Science, 19</em>(1), 7-91.
Retrieved from <a href="https://cames.ippt.gov.pl/index.php/cames/article/view/100" target="_new">https://cames.ippt.gov.pl/index.php/cames/article/view/100</a>