To cite somoclu in publications use:

Wittek P, Gao SC, Lim IS, Zhao L (2017). “somoclu: An Efficient Parallel Library for Self-Organizing Maps.” Journal of Statistical Software, 78(9), 1–21. doi:10.18637/jss.v078.i09.

Corresponding BibTeX entry:

  @Article{,
    title = {{somoclu}: An Efficient Parallel Library for
      Self-Organizing Maps},
    author = {Peter Wittek and Shi Chao Gao and Ik Soo Lim and Li
      Zhao},
    journal = {Journal of Statistical Software},
    year = {2017},
    volume = {78},
    number = {9},
    pages = {1--21},
    doi = {10.18637/jss.v078.i09},
  }