Portative organ builders:

Orgelbauwerkstatt Willehard Schomberg,
Kreisstrasse 53, D-26169 Kamperfehn, Germany
www.willehardschomberg.de

Orgelbau Rohlf, Im Seitzental 9, D-75387 Neubulach, Germany
www.orgelbau-rohlf.de

Orgelmanufaktur Lutz, Ringstrasse 13a, Feuchtwangen, Germany
(Planning and execution of the world's first modern portative organ)

Historical temperaments

Temperament systems with diagrams:
home.arcor.de/wschmidts/index.html

Temperaments with the hapsichord, Link-Site of Oscar Milani:
www.oscarmilani.de

Temperaments, computations:
www personal.umich.edu/~bpl/temper.html

Listening to examples in different temperaments (ger.):
delphi.zsg-rottenburg.de/muslekt8.html (All Lessons)

More Examples to listen (ger.):
www.robertschroeter.de/stimmungen.html

A lot of scales:
www.huygens-fokker.org/scala

Archicembalo and Clavemusicum omnitonum as 31-ET-instrument of the 16th and 17th century:
en.wikipedia.org/wiki/Archicembalo

Other websites:

Portative organ (ital.):
www.portativo.it

Inexpensive music scores for flute and recorder
english.floetennoten.net