References

[1]

W. Kabsch. A solution for the best rotation to relate two sets of vectors. Acta Crystallographica Section A, 32(5):922–923, 1976.

[2]

Gerald R. Kneller. Eckart axis conditions, Gauss' principle of least constraint, and the optimal superposition of molecular structures. J. Chem. Phys., 128(19):194101, May 2008.