He has written research articles about the reliability of Wikipedia. In one them, he compares a Wikipedia article about a breast cancer controversy to an article in Encyclopedia Britannica and two Danish encyclopedias.
Birger Jarl | Birger Sjöberg | Karl-Birger Blomdahl | Charles Birger | Birger, King of Sweden | Birger Jarls Torn | Birger Jarls torn | Birger Jarlsgatan | Birger | Birger Ruud | Birger Ragnvald Sevaldson | Birger of Sweden | Birger Brosa | Birger Bergersen |