Bill Ackman says he has “good reason to believe” plagiarism allegations against his wife, former tenured Massachusetts Institute of Technology professor Neri Oxman, came from an inside source at the esteemed university. Business Insider expanded its investigation into Oxman’s 2010 MIT doctoral dissertation on Friday, finding that aside from the four paragraphs of improperly-cited information it pointed to in its initial probe, there were some 28 other alleged instances where the academic copy-pasted passages — at least 15 of which were ripped from Wikipedia entries. Ackman — whose been on a public crusade against MIT, demanding that it fire its...