Sardinia Imperfs- Unused

Good Day to all. I am wondering if anyone can direct me to a specific site to inform about markings on these Sardinia stamps? I am aware there are many forgeries done with these specific stamps.I have been told to keep in mind to think of them as forgeries before ruling out genuine. However, I was not told exact markings or specifics to be a genuine stamps vs a forgery. Would like to know for future references too. All are imperf. except one. I received them from a sheet expressing Sardinia 1855-61. from a stamp show. Below are a few of the pics. I received 7 of them. 5c,10c twenty c, 40c, and 80c all imperfs.
Any information would truly be appreciated. Thank you in advance.

Sorry, place the perf. one..he is the imperf.
This one looks more genuine than the other one that is perforated

Try this (note, click around on sections to see details)
http://forgeriesofitalianstates.com...Sardinia.htm
Don

Thank you, Don for providing me with such a fabulous marking website! I did not see them as being any of any of those characters with forgeries. It seems they passed that test so far. I was very pleased to read about the dot near the "O" on bollo on the twenty blue and it shows it on my stamp too. Green dull 5c, bister 10, 40 red, and 80 c yellow all have the markings as geniune. But again, it seems that David Cohen from Berlin were known to do them too with retouch on the plates. I don't know if any of these can be his piece of work. Apparently it is really slight changes noticed.
I also read on another site that the 80c yellow which I have two imperfs are considered rare too. Maybe those two mint stamps maybe need to be evaluated more closely. I also read that the perforated green 5 was not done in Italy, so it is a reprint.
Thank you again for your information that was provided