Often discussed, occasionally cited, but rarely read — certainly a highly suspicious combo — I post here the original German language final version (we think):
- Eyferth, K. (1961). Leistungen verschiedener Gruppen von Besatzungskindern in Hamburg-Wechsler Intelligenztest für Kinder (HAWIK). Archiv für die gesamte Psychologie, 113, 224-241.
- Eyferth, K. (1959). Eine Untersuchung der Neger-Mischlingskinder in Westdeutschland. Human Development, 2(2), 102-114.
(there’s a few more earlier reports which I will post later)
The numbers in the final version seem to match those given by Flynn 1980.
My guess is that there’s more of these kinds of old studies around, but there’s not enough curious people around to dig them up (or brave enough to post them if found and they have the wrong results). If you have time, try looking around for WW1 and WW2 US soldier related studies.