Simplify the following text for a Grade 6 native English-speaking person.
Original: The first documented use of the Easter Bilby concept was in March 1968 in Rose-Marie Dusting 's story called Billy The Aussie Easter Bilby . Rose-Marie Dusting , was a 9 year old child when she first wrote `` Billy The Aussie Easter Bilby '' ' in a small Queensland town called Richmond .
Simplified: Author Rose-Marie Dusting wrote a book in 1979 called Billy , the Aussie Easter Bilby .