Langdon and Sophie enter King's College's Research Institute in Systematic Theology, where the reference librarian instantly recognizes Langdon.
Her name is Pamela Gettum, and she's a fan.
Usually, you need to petition or make an appointment to use their services, but Langdon name-drops Teabing and she agrees to do them a favor this one time, wink-wink.
They show her the first two lines of the verse ("In London lies a knight a Pope interred. / His labor's fruit a Holy wrath incurred."), and she's intrigued.
They basically start doing a Google search using their database, and the words "London, Knight, Pope."
Their results include a ton of stuff by Alexander Pope, who wrote counterreligious mock-epic poetry that contained a lot of references to knights and London.
Gettum starts to put two-and-two together. Langdon was famous for the events at the Vatican last year. He's friends with Teabing. They're on a desperate mission. Obviously, he's on a Grail quest.
They sheepishly admit she's right, and show her the rest of the verse. She changes their search parameters to narrow down the options, and then they wait. It'll take about fifteen minutes to get the results.