To cite package ‘oligo’ in publications use:

  Carvalho B. S., and Irizarry, R. A. 2010. A Framework for
  Oligonucleotide Microarray Preprocessing. Bioinformatics.

A BibTeX entry for LaTeX users is

  @Article{,
    author = {Benilton S Carvalho and Rafael A Irizarry},
    title = {A Framework for Oligonucleotide Microarray Preprocessing},
    journal = {Bioinformatics},
    volume = {26},
    number = {19},
    year = {2010},
    issn = {1367-4803},
    pages = {2363-7},
    doi = {10.1093/bioinformatics/btq431},
    publisher = {Oxford University Press},
    address = {Oxford, UK},
  }