The control of terms that define the essential obligations of the parties under the Unfair Contract Terms Directive: Gutiérrez Naranjo: Joined Cases C-154, 307 & 308/15, Francisco Gutiérrez Naranjo v. Cajasur Banco SAU; Ana María Palacios Martínez v. Banco Bilbao Vizcaya Argentaria SA (BBVA) and Banco Popular Español SA v. Emilio Irles López and Teresa Torres Andreu