STAMPS
1936
Netherlands, Relief Fund
1937
Netherlands, Relief fund
1938
Luxembourg, Echternach Abbey
Netherlands, Relief Fund
1939
Luxembourg, Centenary of Independence
Luxembourg, Reign and Royal Marriage
Netherlands, Relief fund
1940
Netherlands, Relief fund
Surinam, Social Welfare Fund (1)
1941
Netherlands, Relief fund
1944
Netherlands, Naval heroes 40c
1946
Netherlands, Queen Wilhelmina definitives
Netherlands, Child Welfare
1947
Belgian Congo, Abolition of slavery (1)
Curaçao, Definitives
Luxembourg, Echternach Abbey
Netherlands, Relief fund
1948
Curaçao, Definitive
Curaçao, Golden jubilee
Netherlands, Definitives
Netherlands, Golden jubilee
Surinam, Golden Jubilee
1949
Netherlands, Queen Juliana definitives
1950
Luxembourg, War orphans Fund
Netherlands New Guinea, En Face definitives
1951
United Nations, Definitives, Clasped hands design
1953
Luxembourg, Echternach Abbey (1)
Luxembourg, Pierre d'Aspelt
1954
Luxembourg, Fencing championships
Netherlands, Queen Juliana definitives
1955
Luxembourg, United Nations (1)
1957
Luxembourg, Baden-Powell
1958
Luxembourg, St Willibrord
1960
Luxembourg, Schuman plan
1961
Luxembourg, Tourism
1963
Luxembourg, Human rights convention
Zaïre, Red cross centenary
1964
Tunisia, National day (1)
1966
Luxembourg, Our Lady of Luxembourg
1969
Netherlands, Erasmus
OTHER PHILATELIC ENGRAVINGS
1935
Netherlands, Engraving of Guyot stamp as practice piece
NON-PHILATELIC ENGRAVINGS
1952
Netherlands, Fl 25 banknote
Notes:
1) Handboek Postwaarden Nederland
You will find Sem Hartz' biography HERE.