Generic composition of boosts: an elementary derivation of the Wigner   rotation
  Because of its apparent complexity, the discussion of Wigner rotation is usually reduced to the study of Thomas precession, which is too specific a case to allow a deep understanding of boost composition. However, by simple arguments and linear algebra, the result for the Wigner rotation is obtained straightforwardly, leading to a formula written in a manageable form, The result is exemplified in the context of the aberration of light. 
Rafael Ferraro, Marc Thibeault