To cite vennLasso in publications use:

  Huling, J. D., Yu, M., Liang, M., & Smith, M. (2018). Risk prediction
  for heterogeneous populations with application to hospital admission
  prediction. Biometrics, 74(2), 557-565.
  https://doi.org/10.1111/biom.12769

A BibTeX entry for LaTeX users is

  @Article{,
    author = {Jared D. Huling and Menggang Yu and Muxuan Liang and Maureen Smith},
    title = {Risk Prediction for Heterogeneous Populations with Application to Hospital Admission Prediction},
    journal = {Biometrics},
    year = {2018},
    volume = {74},
    number = {2},
    pages = {557--565},
    doi = {10.1111/biom.12769},
  }