Schneider, Baruch2023-06-162023-06-1620071607-2510https://hdl.handle.net/20.500.14365/3272We give a short proof of a formula of Poincare-Bertrand in the setting of theory of time-harmonic electromagnetic fields on a piece-wise Liapunov surface, as well as for some versions of quaternionic analysis.eninfo:eu-repo/semantics/closedAccessArticle2-s2.0-34247563517