Joined Cases C-378/07 to C-380/07: Judgment of the Court (Third Chamber) of 23 April 2009 (references for a preliminary ruling from the Monomeles Protodikio Rethimnis — Greece) — K. Angelidaki, A. Aivali, A. Vavouraki, Kh. Kaparou, M. Lioni, E. Makrigiannaki, E. Nisanaki, Kh. Panagiotou, A. Pitsidianaki, M. Khalkiadaki, Kh. Khalkiadaki (C-378/07), Kharikleia Giannoudi (C-379/07), Georgios Karampousanos, Sophocles Mikhopoulos (C-380/07) v Nomarkhiaki Aftodiikisi Rethimnis, Dimos Geropotamou (Directive 1999/70/EC — Clauses 5 and 8 of the framework agreement on fixed-term work — Fixed-term employment contracts in the public sector — First or single use of a contract — Successive contracts — Equivalent legal measure — Reduction in the general level of protection afforded to workers — Measures intended to prevent abuse — Penalties — Absolute prohibition on conversion of fixed-term employment contracts into contracts of indefinite duration in the public sector — Consequences of the incorrect transposition of a directive — Interpretation in conformity with Community law)