OK,I found what I was looking for...just with a bit more effort.
"You can use our standard MR forms or you can use any generic MR form as long as it is not especially designed for another agency or mentions legal jurisdiction other than US's or the photographer/model's country laws."
Well the information is clear, but If there will be some link of another model release sample (pdf) it won´t be bad.. I´m curious whether it is possible to use it on another microstock site as well. Any ideas, opinions? Thanks (my english is not perfect, maybe I´m missing something..)