Chobanov, Georgi, and Ivan Chobanov. 1994. “Newtonian and Eulerian Dynamical Axioms. IV. The Eulerian Dynamical Equations”. Ann. Sofia Univ. Fac. Math. And Inf. 86 (2):41-71. https://ftl5.uni-sofia.bg./index.php/fmi/article/view/506.