2023 – Engelbrecht, Lars: Danmarks Helsager den Tofarvede Udgave 1871–1905 (Postal Stationery of Denmark), two volumes in Danish language 2021), Vol. 1: Helsagernes fremstilling og varianter (417 pages), Vol. 2: Helsagernes anvendelse (431 pages), hardcover, signed by the author, like new. Estimation: 120 Euro
