https://rstudio-pubs-static.s3.amazonaws.com/265713_cbef910aee7642dc8b62996e38d2825d.html
https://analytics4all.org/2016/12/22/r-text-mining-pre-processing/
https://www.tidytextmining.com/topicmodeling.html
https://juliasilge.com/blog/sherlock-holmes-stm/
https://cran.r-project.org/web/packages/ldatuning/vignettes/topics.html#references
https://towardsdatascience.com/latent-dirichlet-allocation-lda-9d1cd064ffa2
https://towardsdatascience.com/introduction-to-natural-language-processing-for-text-df845750fb63
https://towardsdatascience.com/topic-modeling-and-latent-dirichlet-allocation-in-python-9bf156893c24
https://www.youtube.com/watch?v=DWJYZq_fQ2A