To cite package 'ptw' in publications use:

Bloemberg TG, Gerretzen J, Wouters HJP, Gloerich J, van Dael M, Wessels HJCT, van den Heuvel LP, Eilers PHC, Buydens LMC, Wehrens R (2010). “Improved Parametric Time Warping for Proteomics.” Chemometrics and Intelligent Laboratory Systems, 104(1), 65-74.

Wehrens R, Bloemberg TG, Eilers PHC (2015). “Fast parametric warping of peak lists.” Bioinformatics, 31, 3063–3065. doi:10.1093/bioinformatics/btv299.

Corresponding BibTeX entries:

    title = {Improved Parametric Time Warping for Proteomics},
    author = {Tom G. Bloemberg and Jan Gerretzen and Hans J. P. Wouters
      and Jolein Gloerich and Maurice {van Dael} and Hans J. C. T.
      Wessels and Lambert P. {van den Heuvel} and Paul H. C. Eilers and
      Lutgarde M. C. Buydens and Ron Wehrens},
    year = {2010},
    journal = {Chemometrics and Intelligent Laboratory Systems},
    volume = {104},
    number = {1},
    pages = {65-74},
    title = {Fast parametric warping of peak lists},
    author = {Ron Wehrens and Tom G. Bloemberg and Paul H. C. Eilers},
    year = {2015},
    volume = {31},
    pages = {3063--3065},
    journal = {Bioinformatics},
    doi = {10.1093/bioinformatics/btv299},