Bedratyuk, L. P. 2010. “Analog of the Cayley–Sylvester Formula and the Poincaré Series for an Algebra of Invariants of Ternary Form”.
Ukrains’kyi Matematychnyi Zhurnal
62 (11): 1561–1570.
https://umj.imath.kiev.ua/index.php/umj/article/view/2980
.