Why having not included all the Europa issues ?
From 1974 on, all stamps issued by the European countries were issued at different dates and only the topic was defined. In 1984, one identical design (the European bridge) was accepted, but issue dates remained spread over 10 months. So Europa is no more a joint issue. It is to mention here that the latest common European issue with a same design was released in year 2000, and most of them at the same date, therefore this one is considered as a twin issue.
