De, U. C., and S. Ghosh. “D-Homothetic Deformation of Normal Almost Contact Metric Manifolds”. Ukrains’kyi Matematychnyi Zhurnal, vol. 64, no. 10, Oct. 2012, pp. 1330-29, https://umj.imath.kiev.ua/index.php/umj/article/view/2662.