The stamps are numbered by province and issued arbitrarily, not alphabetically as in most other countries. This system is identical to the Dutch albums. The albums were issued from 1931 onwards. The series were not issued completely by province, but the sheets were issued in batches consisting of parts of multiple provinces. The sheets and stamps were reprinted approximately halfway completion. This has resulted in two different editions of the series, as the second edition has a slightly different lay-out and many errors were corrected. The main texts are identical. For both languages two editions exist.