In the search of a dissertation theme, Larry Page had been considering among other things exploring the mathematical properties of the World Wide Web, understanding its link structure as a huge graph.[8] His supervisor, Terry Winograd, encouraged him to pick this idea (which Larry Page later recalled as "the best advice I ever got"[9]) and Larry Page focused on the problem of finding out which web pages link to a given page, based on the consideration that the number and nature of such backlinks was valuable information about that page (with the role of citations in academic publishing in mind).[8] Page told his ideas to Hassan, who began writing the code to implement Page's ideas.[3]