Any publication using results from the DCA webservice should cite the following articles:
[1] F. Morcos, A. Pagnani, B. Lunt, A. Bertolino, D. S. Marks, C. Sander, R. Zecchina, J. N. Onuchic, T. Hwa, and M. Weigt, “Direct-coupling analysis of residue coevolution captures native contacts across many protein families,” Proc Natl Acad Sci U S A, vol. 108, no. 49, pp. E1293–301, 2011. Epub 2011 Nov 21.