Maximum number of cards - exact ruling (different series = differnt card?)

[slap_shot_12]

I've got a deck that I'd like to put a number of darkenss energy into (the special energy kind) and I've got some from a couple of different series (so the card numbers are different but everything else is the same). Can I use four of them in total, or four of them from each different series?

Thanks in advance! :biggrin:

 

[PokePop]

4 total.
It goes by the name.
What set it's from doesn't matter.
Although if it is pre-RS, you would need a reference card or card-dex page.