Guo, J., Jean, J., Nikolic, I., & Sasaki, Y. (2017). Meet-in-the-Middle Attacks on Classes of Contracting and Expanding Feistel Constructions. IACR Transactions on Symmetric Cryptology, 2016(2), 307-337. https://doi.org/10.13154/tosc.v2016.i2.307-337