Citation
If you publish research that uses crux you have to cite it as follows:
Park, C. Y., Klammer, A. A., Käll, L., MacCoss, M. J., & Noble, W. S. (2008). Rapid and accurate peptide identification from tandem mass spectra. Journal of Proteome Research, 7(7), 3022–3027. https://doi.org/10.1021/pr800127y