To cite pear in publications use:

A. I. McLeod (1994). Diagnostic Checking of Periodic Autoregression Journal of Time Series Analysis, Vol. 15, No. 2, pp.221--233.

Corresponding BibTeX entry:

  @Article{,
    title = {Diagnostic Checking of Periodic Autoregression},
    author = {A. I. McLeod},
    journal = {Journal of Time Series Analysis},
    year = {1994},
    volume = {15},
    number = {2},
    pages = {221-233},
  }