Germany's four living former presidents have jointly urged Iran to release two journalists detained in October in connection with a highly publicized stoning case, and a top Iranian official voiced hope they could at least be temporarily reunited with their families for Christmas.Sunday newspaper Bild am Sonntag, for whom the journalists were working in Iran, carried the rare joint appeal by the country's elder statesmen Horst Koehler, Roman Herzog, Richard von Weizsaecker and Walter Scheel.Koehler recalled the "traditionally good relations between the German and the Iranian people" and was further quoted as saying the Iranians should free the journalists before Christmas in a gesture of humanity. Koehler abruptly resigned in May and has kept a very low profile until now.The former presidents also praised Iran for its rich culture and its traditions.