This news article from the University of Florida, Gainesville student news, by Sean Stewart-Muniz, states, "A study published Aug. 19 online in the Proceedings of the national Academy of Sciences, observed two groups of sutdents as they drank lemonade sweetened with sugar and a sugar substitute." The article refers to the stuy as reporting results of trials, and cites the source of the article as being reported on http://www.sciencenews.org.
*This study and its abstract did not use the word 'sugar,' rather they used 'glucose.' - Often news articles choose more familiar words than the precise scientific terms used in studies and this can make them difficult to track down.
This news blog post on the New York Times, by Nicholas Bakalar, describes the study as, "...a randomized clinical trial [that] found that vitamin D and calcium supplements are no better than a placebo for relieving joint problems." The news blog post also discusses the study's results, saying, "The analysis is posted online in The Journal of the Academy of Nutrition and Dietetics." Finally, it states that the 'lead author' was, "Dr. Rowan T. Chlebowski, a medical oncologist at the Los Angeles Biomedical Research Institute."