“…where X , Y , U , V , R , and S , the components of the infinitesimal transformations which are functions of x , y , u , v , r , and s . The procedure is very well-documented, and we refer the reader to several books on the subject matter (see, for example, [10–14]). Performing this analysis leads to a total of 50 determining equations several of which are duplications or linear combinations of others.…”