As I have found it, I'd make a couple of corrections, if you don't mind. The name of this car is SMZ S-3D, later - SeAZ S-3D, as the factory changed its name. Russian Z looks exactly the same as '3', but still it's a figure in this index - there have also been S-1 and S-4 at least. The car was intended for disabled people and was produced through 1970-1996.
The word 'invalidka' mentioned before is nothing more than a slang analog for 'a car for disabled people' and doesn't refer to any exact make and model, but to all cars of this type in general.
As for one of grobmotorix's post, S-3A (again not S-ZA) was a different car - the precursor of this version, so those German sources are sadly wrong.
