TY - JOUR TI - INTRODUCTION JO - Glasgow mathematical journal PY - 2013 SP - 1 EP - 2 VL - 55 IS - A UR - http://geodesic.mathdoc.fr/articles/10.1017/S0017089513000463/ DO - 10.1017/S0017089513000463 ID - 10_1017_S0017089513000463 ER -