I've been reading about BSD Lisenses on Wikipedia recently and the article said that 4 and 3-clause BSD Licenses' texts are in the public domain. But there weren't any links that would prove this apart from the fact that they have Public Domain as their publisher in the article. So, is that really true? Also, 2-clause BSD license doesn't even have Public Domain as it's publisher. Is 2-clause BSD license's text in the Public Domain?