Fields of 2-Planes on Compact Simply-Connected Smooth 4-Manifolds. Yasuo Matsushita — 1988 Mathematische Annalen
Fields of 2-planes and two kinds of almost complex structures on compact 4-dimensional manifolds. Yasuo Matsushita — 1991 Mathematische Zeitschrift
Equivalence classes of Fields of 2-planes and two kinds of almost complex structures on compact four-dimensional manifolds. Yasuo Matsushita — 1995 Manuscripta mathematica