Normality of almost contact $3$-structure

Kentaro Yano, Shigeru Ishihara, Mariko Konishi
1973 Tohoku mathematical journal  
On the normality of an almost contact 3-structure on QR-submanifolds
doi:10.2748/tmj/1178241375 fatcat:liimcwyv4jeq7iw6lt55f4ravi