It is well-known that the BGG category $\mathcal{O}$ was introduced in the early 1970s by Joseph Bernstein, Israel Gelfand and Sergei Gelfand. I google for a while but I cannot find out the original paper for defining Category $\mathcal{O}$. Does anyone know where to find or what is the name of the paper? Please help me.



Looking for access to original paper for Category O
Joseph N. Bernstein, Israel M. Gelfand, and Sergei I. Gelfand, [*Category of $\mathfrak{g}$-modules*,](http://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=faa&paperid=2144&option_lang=eng) Functional Analysis and its Applications **10** (1976), 87–92.  [MR0407097](https://mathscinet.ams.org/mathscinet-getitem?mr=0407097)   

[(English translation)](https://link.springer.com/article/10.1007%2FBF01077933)


