There is a discussion running over a couple of threads on TMP about the Erzherzog Karl/Archduke Charles legions of 1800 and 1809, which were raised in Bohemia and Moravia (now the Czech Republic) in 1800 and 1809. It is a complex subject as the two formations get confused and mixed up with 1809 Landwehr (conscripted militia). I must admit to getting some of it wrong in Osprey MAA299 (but it was 30 years ago and more material is much more accessible now!).
One source employed for the 1809 Legion (6 Bohemian and 3 Moravian volunteer battalions) is the Heer and Tradition plate from 1966:
One poster says: "Heer und Tradition have this uniform plate which confirms Enrico Acerbi's version" - well, no, Acerbi, who has been writing quite a lot on the army in recent years, has taken his information from the H&T plate and that does not confirm the accuracy of either. This plate is by Herbert Knotel, (Knotel the Younger), best known for illustrating Elting's 'Napoleon's Uniforms', originally in the years after WW2.
The best-known plate of the 1800 Legion (22 battalions and one Jaeger battalion of militia) is by Richard Knotel in his Uniformenkunde series in the 1890s. It was a kind of subscription set of plates and would be accompanied by requests to his subscribers for information.
Neither Knotel gives his sources, but Herbert Knotel is well-known to have used the famous 1895 work by Ottenfeld & Teuber 'Die Oesterreichische Armee'. Richard's subscribers also recommended material from the same work. It is possible to see the Ottenfeld references (from the Hathitrust digital copy https://babel.hathitrust.org/cgi/pt?id=mdp.39015024521240&seq=175&q1=Landwehr):
Aside from the central figure of the Prague Student in the Herbert Knotel plate, those figures are all copied from Ottenfeld, which is described as a coffee-table book as it has no sources. However, Knotel has introduced some slight changes and copied known errors in Ottenfeld: The Vienna Volunteer/Freiwillige has acquired the greatcoat of the Lower Austria Landwehrman shown in the colour plate. This is fair enough as only the 1st Vienna Volunteer battalion had line infantry uniforms and the rest had the Landwehr greatcoat ('Die Landwehr Anno Neun' by von Ravelsberg (1909) and 'Karger, Johann. Entwicklung der Adjustierung, Rüstung und Bewaffnung der Österreichisch-ungarischen Armee von 1700 bis 1809. (1903)). However, the Moravian Landwehrman in the b/w has become a Volunteer/Freiwillige. The key error is that the Freiwillige wore pointed plain red facings on the cuffs and colour to show their volunteer status. The Lower Austrian Landwehr officially wore rounded red cuffs and collars, but Bohemia/Moravia was officially light blue.
That will do for now - next, a trip through the 1800 Legion and back to 1809.