Hi,
I think I understand the pros and cons of the weathstone bridge. I will look for some information about the jfet as a current source, it seems to be quite useful. But indeed with a stable voltage source and if I use 1% resistors maybe I can have a quite good accuracy for the temperature measurement. I will make all the calculation needed with this page :
www.sanprotechmarketing.com/article_writing/ametherm/NTC_thermistor_wheatstone_bridge_oct31.pdf
And I will come back to tell you what accuracy I can have.
Thanks