Wing tip design and wingtip vortices

[saeae...@gmail.com]

I found this experiment being done on different wing tip design. It
seems they've done our job for us already, check it out.

http://ojas.ucok.edu/96/T96/Jdavis.htm

In a nutshell we should be using the up swept wingtip.

Now I am searching for other sources that will back up his claim.