See, for instance, Rui Gerra da Fonseca: Having established the legislative nature of the statutes of a public undertaking based on a decree law, it is unconstitutional for them to be amended by any instrument other than a decree law, just as rules permitting their amendment by a mere instrument of private law are also unconstitutional, Autonomia Estatutária das Empresas Publicas e Descentralização Administrativa, Coimbra 2005.
Vt nt Rui Gerra da Fonseca: Dekreetseadusega formaliseeritud avalik-õigusliku äriühingu põhikirja muutmine muu õigusakti kui dekreetseadusega on vastuolus põhiseadusega, nagu ka sätted, mis lubavad neid muuta vaid eraõiguse valdkonna aktiga, Autonomia Estatutįria das Empresas Publicas e Descentralizaēćo Adminstrativa, Coimbra 2005