To cite strat in publications use:

Xiang Zhou (2012). A Nonparametric Index of Stratification. Sociological Methodology, 42(1), 365-389. URL http://smx.sagepub.com/content/42/1/365.short.

Corresponding BibTeX entry:

  @Article{,
    title = {A Nonparametric Index of Stratification},
    author = {Xiang Zhou},
    journal = {Sociological Methodology},
    year = {2012},
    volume = {42},
    number = {1},
    pages = {365--389},
    url = {http://smx.sagepub.com/content/42/1/365.short},
    doi = {10.1177/0081175012452207},
  }