Can anyone help on this ?

I have red in a few places that the theoretical global temperature increase for a 'doubling' of CO2, with no additional feedbacks considered, would be about 1 degree Fahrenheit. With additional feednacks, the commonly quoted number is 3 degrees centigrade.

I can't find any references to the theroretical forcing from CO2 alone (1 degree F). I was sure it had been quoted in an IPCC report but can't find it.

Can anyone point me to a reference for this ? Thanks.