Polyakov E, Vorontsov-Velyaminov P. A quantum gas in an external field at finite temperatures. An exact expression for density and exited states. Num. Meth. Prog. [Internet]. 2007 Nov. 16 [cited 2024 Apr. 29];8(14):334-51. Available from: https://en.num-meth.ru/index.php/journal/article/view/275