Primarily Petroliana Shop Talk Forums Shop Talk Petroliana Forums Petroliana Value Questions rare old sinclair signs

I found 3 signs in an upstate ny barn I can't find any info on these signs because they are so rare they are all porclein and the diameter of the circular ones are apporx 16 in. I know I found something great the only place I have located these are in my book which is in my encyclopedia of petroliana price guide from 1999 over 15 years old. Can anyone help me out and give me an idea of the value of these signs in todays market thanks so very much I look forward to hearing from people