2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227201The contents of the paper is now covered in two separate papers arXiv:0904.2188 and arXiv:0904.2602. Please refer to those. Note that you can still access the original version arXiv:0711.4082v1.REPLACED by two separate papers arXiv:0904.2188 and arXiv:0904.2602 as 0711Exactly Solvable and Integrable SystemsMathematical Physicstext