Sorry, but there has been more research done and there has been no successful tests on long-term use, big reason being that they didn't discover melatonin and pot's effects on it, until recently. 1986, I think, was when it was discovered and early 90's is when, I think, it was linked up with pot. It has been years since I did the research so I forgot.
But, did you check the resource page of the link? Their resources are a PBS program and Marijuana Anonymous. Do some of your own research but don't believe everything you read over the internet.