> (I want to thank Mr. Felscher for his response to my question on who
> was Hauber. It would be interesting to know how Hauber himself stated
> his "principle".)
The following short article by Cyril F.A. Hoormann, "On Hauber's statement
of his theorem" [Notre Dame J. Formal Logic, vol 12, pp 86-88, 1971],
might answer the question.
Julio GC