M. . Zapata Granada and H. A. . López Duque, “The principle of planning as a cause of absolute nullity of state contracts: a jurisprudential analysis from the principle of taxation”, Rev. Facultad Derecho Cienc. Políticas, vol. 52, no. 136, pp. 124–154, Jan. 2022, doi: 10.18566/rfdcp.v52n136.a06.