足立 二郎. A certain surgery construction of contact 3-manifolds (Geometry on real closed field and its application to singularity theory). 数理解析研究所講究録. 2011. 1764. 1764. 139-148
足立 二郎. 4次元多様体の手術とEngel構造 (Applications of singularity theory to differential equations and differential geometry). 数理解析研究所講究録. 2009. 1664. 1664. 105-116
足立 二郎. On classification of horizontal loops in the standard Engel space (Development of Cartan Geometry and Related Mathematical Problems). 数理解析研究所講究録. 2006. 1502. 1502. 29-40
足立 二郎. On various kinds of the Gray-type Theorem (特異点論における新しい方法と対象 研究集会報告集). 数理解析研究所講究録. 2004. 1374. 1374. 114-125