CONCLUSIONS AND OUTLOOKS
We are now in the position to draw some conclusions for this work. First, we have given some historic review of the factorization method. It should be noted that the lists of references in this direction are far from complete even though we have mentioned almost all important contributions. After that we have proposed our new factorization method to study some important quantum systems. It should be pointed out that the procedure of our present method is converse to that of the Infeld-Hull method.