In early July 1999, a collector in Edmonton discovered a
$20 Bird Series note (Prefix ESZ) that was missing the back plate number.
In the following months, the following has been determined:
With Back Plate Number: ESZ, EVA, EVC, EVD, EVE, EVH
Without Back Plate#: ESZ, EVA, EVB, EVC, EVD, EVE, EVH
(note that no EVB prefix has been found
with a back plate #)