The following references should be cited if the use of DelPhiPKa results to a publication.
In particular, the first reference describes the methodology and the second reference describes the web server.
1. Lin Wang, Lin Li, and Emil Alexov. "pKa predictions for proteins, RNAs and DNAs with the Gaussian dielectric function using DelPhiPKa." Proteins. (2015) Sep 26, doi: 10.1002/prot.24935
2. Lin Wang, Min Zhang, and Emil Alexov. "DelPhiPKa Web Server: Predicting pKa of proteins, RNAs and DNAs." Bioinformatics. (2015) Oct 29, doi: 10.1093/bioinformatics/btv607