Kūchū Buranko (Korean title: 공중그네; original title: 空中ブランコ) by Hideo Okuda (奥田英朗) has been read or recommended by 6 Korean celebrities, including Kang Hye-jung, Park Hae-jin, IU. Below, each entry shows where they mentioned it and what they said.
Included among three books introduced with keywords in a Yes24 video. (Source: YouTube)
From Park Hae-jin's shared reading list: a book that's fun no matter when you read it. (Source: Seoul Economic Daily)
On IU's high school library loan record, shown on Weekly Idol in 2012. (Source: IU book list compiled on Naver Blog)
A book Cha Tae-hyun gave him; he said he related strongly to the fourth episode and cried openly. (Source: Naver Entertainment)