To cite package ‘groHMM’ in publications use:

  Chae M, Danko CG, Kraus WL groHMM: a computational tool for
  identifying unannotated and cell type-specific transcription units
  from global run-on sequencing data BMC Bioinformatics, 2015, 16:222

A BibTeX entry for LaTeX users is

  @Article{,
    title = {groHMM: a computational tool for identifying unannotated and cell type-specific transcription units from  
               global run-on sequencing data},
    author = {Minho Chae and Charles G. Danko and W. Lee Kraus},
    journal = {BMC Bioinformatics},
    year = {2015},
    volume = {16},
    number = {222},
  }