To cite the Octave NURBS package use:

[1] M. Spink, D. Claxton, C. de Falco, R. Vazquez,
    The NURBS toolbox,
    http://octave.sourceforge.net/nurbs/index.html.

[2] C. de Falco, A. Reali, and R. Vazquez.
    Geopdes: A research tool for isogeometric analysis of pdes.
    Advances in Engineering Software, 42(12):1020-1034, 2011.

BibTeX entries for LaTeX users are:

@misc{NT,
      Author = {Spink, M. and Claxton, D. and de Falco, C. and V{\'a}zquez, R.},
      Howpublished = {\url{http://octave.sourceforge.net/nurbs/index.html}},
      Title = {The {NURBS} toolbox}}

@article{geopdes,
	Author = {C. de Falco and A. Reali and R. V{\'a}zquez},
	Journal = {Advances in Engineering Software},
	Number = {12},
	Pages = {1020-1034},
	Title = {GeoPDEs: A research tool for Isogeometric Analysis of PDEs},
	Volume = {42},
	Year = {2011}}