“in the case of a decision given in the absence of the defendant or his legal representative, the defendant was not duly served with the document which instituted the proceedings or an equivalent document in sufficient time to enable him to arrange his defence; but such a failure to effect service cannot constitute a ground for refusing recognition or enforcement where service was not effected because the defendant had concealed his whereabouts from the person who instituted the proceedings in the State of origin”
“unless the defendant failed to commence proceedings to challenge the judgment when it was possible for him to do so”