GRIGORY E., VOLOVIK. "Microscopic Physics." The Universe in a Helium Droplet. : Oxford University Press, 2009-02-26. Oxford Scholarship Online. 2010-01-01. Date Accessed 21 May. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199564842.001.0001/acprof-9780199564842-chapter-7>.
GRIGORY E., V.(2009-02-26). Microscopic Physics. In The Universe in a Helium Droplet. : Oxford University Press. Retrieved 21 May. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199564842.001.0001/acprof-9780199564842-chapter-7.
GRIGORY E., VOLOVIK. "Microscopic Physics." In The Universe in a Helium Droplet. : Oxford University Press, 2009-02-26. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199564842.001.0001/acprof-9780199564842-chapter-7.
GRIGORY E. V. Microscopic Physics. In: Volovik GE. The Universe in a Helium Droplet. Oxford University Press; 2009. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199564842.001.0001/acprof-9780199564842-chapter-7. Accessed May 21, 2013.