Wikipedia:Bak pasir
Proyeksi astral
The Journal of Chemical Physics -- February 8, 1997 -- Volume 106, Issue 6, pp. 2400-2410 doi:10.1063/1.473151
Proyeksi astral
The Journal of Chemical Physics -- February 8, 1997 -- Volume 106, Issue 6, pp. 2400-2410 doi:10.1063/1.473151