Saha, Chandan Algorithms and Complexity, MPI for Informatics, Max Planck Society;
Kayal, N., & Saha, C. (2012). On the Sum of Square Roots of Polynomials and Related Problems. The ACM Transactions on Computation Theory, 4(4), 9:1-9:15. doi:10.1145/2382559.2382560.