To cite gamair in publications use:

Wood SN (2006). Generalized Additive Models: An Introduction with R, First edition. Chapman & Hall/CRC, Boca Raton, Florida. ISBN 1-58488-474-6.

Corresponding BibTeX entry:

  @Book{,
    title = {Generalized Additive Models: An Introduction with R},
    author = {S. N. Wood},
    publisher = {Chapman & Hall/CRC},
    edition = {First},
    address = {Boca Raton, Florida},
    year = {2006},
    note = {ISBN 1-58488-474-6},
  }