Complex sentence: Since then he has been included in major exhibitions in Australia and overseas (primarily in Japan and Europe), culminating in a major retrospective in Basel (2005) and in Hanover's Sprengel Museum (2006).
Split into simpler sentences: Since then he has been included in major exhibitions in Australia and overseas (primarily in Japan and Europe). His work was subsequently the subject of a major retrospective in Basel (2005) and in Hanover's Sprengel Museum (2006).