Should I use a comma here?

Some say "yes" and some say "no".

Consider a list of things followed by "and" and a final item, like these:

cheese, eggs, bacon, and ham
Monday, Tuesday, Wednesday, and Thursday
Portugal, Spain, and France

The comma before "and" is called a "serial comma". Most American English writers use it, but it is less widely used in British English. Some British English style guides say you should always use it, some say you should omit it, and some say you should omit except where to do would cause ambiguity.

That's what I thought. So if I'm writing a paper in US, I should do it that way. Correct?

The serial comma (or Oxford comma) is standard in most US writing. Most American style guides advise that it should be used, but I note that the most recent edition of the AP (Associated Press) Style Book, of May 2013 recommends leaving it out unless absolutely necessary: "We generally don't use the Oxford comma in a simple series: The U.S. flag is red, white and blue."

So go ahead and use it if you want to.

Absolutely not, Glug

I agree; a comma is not necessary.