To cite modTempEff in publications use:

Vito M. R. Muggeo (2010). Analyzing Temperature Effects on Mortality Within the R Environment: The Constrained Segmented Distributed Lag Parameterization. Journal of Statistical Software, 32, 12: 1-17.
Vito M. R. Muggeo (2008). Modelling temperature effects on mortality: multiple segmented relationships with common break points. Biostatistics, 9: 613-620.

Corresponding BibTeX entries:

  @Article{,
    title = {Analyzing Temperature Effects on Mortality Within the {R}
      Environment: The Constrained Segmented Distributed Lag
      Parameterization.},
    author = {Vito M. R. Muggeo},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {32},
    number = {12},
    pages = {1--17},
    url = {http://www.jstatsoft.org/v32/i12/},
  }
  @Article{,
    title = {Modelling temperature effects on mortality: multiple
      segmented relationships with common break points.},
    author = {Vito M. R. Muggeo},
    journal = {Biostatistics},
    year = {2008},
    volume = {9},
    pages = {613--620},
  }