Here are a few links to well done white papers
https://nem.io/wp-content/themes/nem/files/NEM_techRef.pdf
https://ark.io/Whitepaper.pdf

In my mind the key elements that comprise a good white paper are

1. overview of technology
2. discussion of use cases
3. roadmap for future development
4. description of team and biographies
5. references to substantiate the technical points
6. discussion of what makes the currency unique - what is the value proposition?  

Latex is preferred due to the professional grade typesetting, but not essential.