Jayant V Narlikar. "From Black Clouds to Black Holes".World Scientific Series in Astronomy and Astrophysics (3rd ed.). 13. Archived from the original on 19 May 2012. Retrieved 30 October 2016.
Jayant V Narlikar. "From Black Clouds to Black Holes".World Scientific Series in Astronomy and Astrophysics (3rd ed.). 13. Archived from the original on 19 May 2012. Retrieved 30 October 2016.