These are a handful of sources which deal with Aset - Isis and which I have been/am working my way through. There does exist more articles and hard to come by books but sofar I´ve been unable to get hold of them.

One which I am keen to find is:
"Muenster, Maria, Untersuchungen zur Göttin Isis vom Alten Reich bis zum Ende des Neuen Reiches", Münchener Ägyptologische Studien 11 (1968).
Any tips in this respect would be most gratefully accepted!

Ich Bin Isis - Jan Bergman
(Studien Zum Memphitishen Hintergrund Der Griechischen Isisaretalogien)
Acta Universitatis Upsaliensis 1968

Isis Mère des Diexu - Francoise Dunand
Editions Errance, Paris 2000 ISBN 2-87772-184-1

Isis Mythe et Mystères - France Le Corsu
Collection d´Études Mythologiques, Société d´Édition 'Les Belles Lettres', Paris 1977

Inskriptioner från Isistemplet - Per Linder
Nya Doxa 1997 ISBN 91-578-0024-3

Island of Isis Philae, Temple of the Nile - William MacQuitty
MacDonald and Jane´s Publishers Ltd, London 1976 ISBN 00 356 081982

Isis Among the Greeks and Romans - Friedrich Solmsen
Harward University Press 1979 ISBN0-674-46775-2

Isis in the Ancient World - R.E. Witt
The John Hopkins University Press 1971 ISBN 0-8018-5642-6