Please tell me if there are any articles/documents from the vatican council II about stem cell research?

No. The council was held before the era of biotechnology. Work with stem cells not from fetuses aren't a problem for anybody that I know of. Fetal tissue may still hold promise in transplants for a few brain diseases -- religionists have forced bans on this research in the past. With autologous stem cells coming into use, it'll be moot.