Rüb, Christine Algorithms and Complexity, MPI for Informatics, Max Planck Society;
https://rdcu.be/dwOxQ (Publisher version)
Rüb, C. (1994). Lower Bounds for Merging on the Hypercube. In M. Bonuccelli, P. Crescenzi, & R. Petreschi (Eds.), Algorithms and Complexity (pp. 213-222). Berlin: Springer.