Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Berts dagbok (Swedish: Bert's diary), translated as In Ned's Head, is a diary novel, written by Anders Jacobsson and Soren Olsson and originally published in 1987, it tells the story of Bert Ljung from 14 January to 4 June during the calendar year he turns 12 during the spring term in the 5th grade at school in Sweden.
Who is the illustrator of Berts dagbok?