Kotake, Kei Stellar Astrophysics, MPI for Astrophysics, Max Planck Society;
Suwa, Y., Takiwaki, T., Kotake, K., & Sato, K. (2007). Gravitational wave background from population III stars. Astrophysical Journal, 665(1 Part 2), L43-L46. doi:10.1086/521078.