- [Internal friction universality - RevModPhys](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5377/2002%2B-%2BPohl%2B-%2Brevmodphys.74.991.pdf)


- 2006 [Universal behavior of internal friction in glasses below Tg : anharmonicity vs relaxation](https://arxiv.org/pdf/cond-mat/0610693.pdf)

**diffs between strong and fragile glasses - the relative role of defects?**

1999 [Theory of Sound Attenuation in Glasses: The Role of Thermal Vibrations](https://epub.uni-regensburg.de/1832/1/fabian22.pdf)

- 2005 [Anharmonic versus relaxational sound damping in glasses. II. Vitreous silica](https://www.researchgate.net/publication/1881156_Anharmonic_versus_relaxational_sound_damping_in_glasses_II_Vitreous_silica)
René Vacher, Eric Courtens, and Marie Foret

- Internal friction plot - 1986 [Low temperature properties of glasses-unsolved problems - A K RAYCHAUDHURI](https://www.ias.ac.in/article/fulltext/jcsc/096/06/0559-0564)

![cc](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5475/friction.png 'bb')

## crystals vs glasses?