Whenever you cite a work that has appeared in more than one version, you should cite the version you’ve consulted. Thus, if you are citing an online article republished from a printed government report, provide the publication details for the online version only. As always, follow the MLA format template. 

In the example below, for the online version of an article originally published in the print publication Morbidity and Mortality Weekly Report and republished on the website MMWR Weekly, the entry begins with the title of the article, followed by the name of the website and its publisher, the date the article was posted online, and the URL:

“Outbreak of West Nile-Like Viral Encephalitis — New York, 1999.” MMWR Weekly, Centers for Disease Control and Prevention, 30 Sept. 1999, www.cdc.gov/mmwr/preview/mmwrhtml/mm4838a1.htm.