In 1991 the Bogdanovs published a book, Dieu et la Science (God and Science), drawn from interviews with Catholic philosopher Jean Guitton, which became a French bestseller. This book provoked a dispute of its own when University of Virginia astronomy professor Trinh Xuan Thuan accused the Bogdanovs of plagiarizing his 1988 book The Secret Melody: And Man Created the Universe. After a legal battle in France, during which a judge initially ruled in Thuan's favour, Thuan and the Bogdanovs settled out of court, and the Bogdanovs later denied all wrongdoing. Thuan suggests that the plagiarism suit pressed the brothers to obtain doctorates as fast as possible, since (according to Thuan) the back cover of the book claimed that the Bogdanovs held doctorates when they did not. In 1993, the brothers began work toward doctorates, first working under the mathematical physicist Moshé Flato [ fr ] of the University of Burgundy. Flato died in 1998, and his colleague Daniel Sternheimer (of CNRS) took over the job of supervising the Bogdanovs. According to Sternheimer, the twins viewed themselves as "the Einstein brothers" and had a propensity to voice vague, "impressionistic" statements; he considered guiding their efforts "like teaching My Fair Lady to speak with an Oxford accent." As he told The Chronicle of Higher Education, Sternheimer did not consider himself an expert in all the topics Grichka Bogdanov included in his thesis, but judged that those portions within his specialty were PhD-quality work.