What does this mean?

I was reading this article which compares the nutritional value of different drinks, when I read this quote (with no apparent references):

Australian researchers found that mixing liquor with diet drinks can intensify the alcoholic effect by 50%

Is this true? I immediately started searching for said study, but haven't yet found it. Is anybody else bugged by the lack of references on Men's Health articles?

And anyways, what does it mean when something "intensifies the alcoholic effect"? Does it magically increase the congener count of the beverage? Is less water absorbed thus making you thirstier, thus making you drink more? And the real question, will I get drunk faster? I want to know!

I wish I could find those mysterious Australian researchers.