exploring-our-moon-today-to-learn-more-about-earths-youth-billions-of-years-ago

http://theconversation.com/exploring-our-moon-today-to-learn-more-about-earths-youth-billions-of-years-ago-43510

https://academic.oup.com/astrogeo/article/54/1/1.31/194436

https://www-curator.jsc.nasa.gov/lunar/