In BNJ 2017 Martyn Frederickson published a quarter-noble of Henry VI that he tentatively assigned to the Trefoil Issue, an issue of which no quarter-nobles were previously known. A reverse die duplicate of the Frederickson coin appeared for sale in a provincial auction in 2018 and prompted the following re-examination of the attribution.
A quarter-noble assigned to the Trefoil Issue of Henry VI re-examined – David Guest
BNS Research Blog 