The girl filed as Nathalie Idoux on EGAFD: http://www.egafd.com/actresses/details.php/id/n00625
appeared on four Supersex magazine issues (nr. 93, 107, 118 and 136) as Nathalie Ivosevich.
Proof that it's indeed the same girl can be found on VEF, where pictures of her appearance in Supersex were posted, though there they name her with a different spelling, Ivozevitch:
http://vintage-erotica-forum.com/t44099 ... vitch.html
but the spelling in the Supersex issues is 'Ivosevich'. I'm sure since I own them all.