JUDGMENT OF THE COURT (Fifth Chamber) of 10 December 1998 in Joined Cases C-127/96, C-229/96 and C-74/97 (references for a preliminary ruling from the Tribunal Superior de Justicia de Murcia, the Arbeitsgericht Frankfurt am Main and the Juzgado de lo Social No 1 de Pontevedra): Francisco Hernández Vidal SA v Prudencia Gómez Pérez, María Gómez Pérez, Contratas y Limpiezas SL (C-127/96), Friedrich Santner v Hoechst AG (C-229/96) and Mercedes Gómez Montaña v Claro Sol SA, Red Nacional de Ferrocarriles Españoles (Renfe) (C-74/97) (Safeguarding of employees' rights in the event of transfers of undertakings)