In chapter 4 of "Modern Quantum Mechanics" by Sakurai, in the section where the SO(4) symmetry in Coulomb potential is discussed, the following commutation relations are given:
## [L_i,L_j]=i\hbar \varepsilon_{ijk} L_k##
## [M_i,L_j]=i\hbar \varepsilon_{ijk}M_k##
## [M_i,M_j]=-i\hbar...