Biryukov, A., D. Khovratovich, and L. Perrin. “Multiset-Algebraic Cryptanalysis of Reduced Kuznyechik, Khazad, and Secret SPNs”. IACR Transactions on Symmetric Cryptology, Vol. 2016, no. 2, Feb. 2017, pp. 226-47, doi:10.13154/tosc.v2016.i2.226-247.