Berts ytterligare betraktelser (Swedish: Bert's additional contemplations ) is a diary novel, written by Anders Jacobsson and Sören Olsson and originally published in 1991, it tells the story of Bert Ljung from 1 September to 31 December during the calendar year he turns 13. The book uses the 1989 almanac following the Gregorian Calendar. As standard, Bert opens the chapters with the words "Hej hej hallå dagboken!" and finishes with "Tack och hej – leverpastej". Bert writes diary for each day during this calendar year, and most notes depicts what happened yesterday.