Chung Y, Rabe-Hesketh S, Dorie V, Gelman A and Liu J (2013). “A nondegenerate penalized likelihood estimator for variance parameters in multilevel models.” Psychometrika, 78(4), pp. 685–709. http://gllamm.org/.

Corresponding BibTeX entry:

  @Article{,
    title = {A nondegenerate penalized likelihood estimator for
      variance parameters in multilevel models},
    author = {Yeojin Chung and Sophia Rabe-Hesketh and Vincent Dorie
      and Andrew Gelman and Jingchen Liu},
    year = {2013},
    journal = {Psychometrika},
    volume = {78},
    number = {4},
    pages = {685--709},
    publisher = {Springer},
    url = {http://gllamm.org/},
  }