Judgment of the Court (First Chamber) of 20 January 2005 in Case C-302/02 (reference for a preliminary ruling from the Oberster Gerichtshof): in the proceedings brought on behalf of Nils Laurin Effing (Family benefits — Grant by a Member State of advances on maintenance payments for minor children — Child of a prisoner — Conditions of granting the maintenance payment — Prisoner transferred to another Member State to serve his sentence — Article 12 EC — Articles 3 and 13 of Regulation (EEC) No 1408/71)