How do you create a spice model of a lm234? This model would need to be used with both LTspice and Labcentre's Proteus software
There is a SPICE model of the LM334 here, which is part of the same family (LM134,LM234,LM334) and may be suitable for your use.
Incidentally, this came from LTWiki, which has some very useful info/links to large libraries (with many many extra models) and advanced LTspice use.