On nilpotency in Leibniz algebras
  The main result of this paper is to prove that if a (right) Leibniz algebra $L$ is \textit{right nilpotent} of degree $n$, then $L$ is \textit{strongly nilpotent} of degree less or equal to $4n^2-2n+1$. 
C. J. A. B\'er\'e, M. F. Ouedraogo and M. Ouattara
math.RA