The Unitrade 2018 Specialized Catalogue of Canadian Stamps features the Established Scott Numbering System. It also includes stamps issued for Canada’s 150th birthday. Editor D. Robin Harris writes: “This year we have added a notation to indicate which constant plate varieties appear on all panes/cylinders of their specific larger printing sheet. In addition, we continue to add the latest Canada Post new issues, updated images with better scans when they become available, and correct minor typographical mistakes, some of which have been around for far too long.”
The Specialized catalogue is a leading resource for collectors of Canadian stamps and lists the major varieties that have been reported to the editors for Canada/BNA stamps. The catalogue lists major colour varieties, perforation changes, errors and many constant plate varieties including significant/major re-entries.