To cite package SLqPCR in publications use:

  Kohl, M., (2007). SLqPCR: Functions for analysis of real-time
  quantitative PCR data at SIRS-Lab GmbH. R package, SIRS-Lab GmbH.
  Jena.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {SLqPCR: Functions for analysis of real-time quantitative PCR data at SIRS-Lab GmbH},
    author = {M. Kohl},
    language = {English},
    year = {2007},
    organization = {SIRS-Lab GmbH},
    type = {R package},
    address = {Jena},
    url = {www.sirs-lab.com},
  }