Performance evaluation of an eight-tube ground heat exchanger using TRT data, Koutaro Tsubaki(佐賀大学), Toshihide Morikawa(森川鑿泉工業所), Aya Yabuki(森川鑿泉工業所), Yasuo Tanaka(三井化学資産), Yusuke Satoh(三井化学資産), Hiroaki Okubo(ワイビーエム), Heat Transfer Research, 52, 13, 1-10, (2021).