LDS is Later Day Saints, also known as the Mormons. They are THE best place to get genealogy help and sources.
They have an absolutely terrific library in Salt Lake City: free to use for everyone and full of helpful assistants.
If you need copies of things, they charge a nominal fee. If you go to a local Family History Center (part of your local Mormon/LDS church) you can rent microfilms from the Salt Lake library for a nominal fee.