To cite HIBAG in publications use:

  Zheng X, Shen J, Cox C, Wakefield J, Ehm M, Nelson M, Weir BS. HIBAG
  -- HLA Genotype Imputation with Attribute Bagging. The
  Pharmacogenomics Journal. (2014) 14, 192-200

A BibTeX entry for LaTeX users is

  @Article{,
    title = {HIBAG -- HLA Genotype Imputation with Attribute Bagging},
    author = {Xiuwen Zheng and Judong Shen and Charles Cox and Jonathan Wakefield and Margaret Ehm and Matthew Nelson and Bruce Weir},
    journal = {The Pharmacogenomics Journal},
    year = {2014},
    url = {https://www.nature.com/articles/tpj201318},
  }

  Zheng, X. Imputation-Based HLA Typing with SNPs in GWAS Studies. In:
  Boegel S. (eds) HLA Typing. Methods in Molecular Biology. (2018) Vol
  1802. Humana Press, New York, NY.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Imputation-Based HLA Typing with SNPs in GWAS Studies},
    author = {Xiuwen Zheng},
    journal = {Methods in Molecular Biology},
    year = {2018},
    url = {https://doi.org/10.1007/978-1-4939-8546-3_11},
  }