[jonathanstrange]

Of course not. They are both in German, though, and it didn't help that Wessel refused to change his name when officials of the GDR asked him to, because that would have contradicted his views about proper names. [The best formulation of FOL with NTPT is in the 1999 edition of Logik.]

Wessel, Horst (1989, 1999): Logik. Logos Berlin.

Sinowjew (Zinov'ev), Alexander Alexandrowitsch (1973): Foundations of the Logical Theory of Scientific Knowledge (Complex Logic). Springer.

Sinowjew (Zinov'ev), A. A. (1970): Komplexe Logik. Grundlagen einer logischen Theorie des Wissens. Vieweg.

http://www.zinoviev.ru/eng/index.html

[stakhanov]

Thank you! Much appreciated! What a happy coincidence that I speak German, too.