TY - JOUR AU - Tadeusz Rumak TI - On the ยต-observability of some non-linear difference equations JO - Annales Polonici Mathematici PY - 1972 SP - 315 EP - 324 VL - 26 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.4064/ap-26-3-315-324/ DO - 10.4064/ap-26-3-315-324 LA - en ID - 10_4064_ap_26_3_315_324 ER -