Lin, J. F., Z. Mao and E.E. Alp (2013), Mössbauer spectroscopy in studying electronic spin and valence states of iron in the Earth’s lower mantle, Mössbauer spectroscopy: Applications in Chemistry, Biology, Industry, and Nanotechnology, V. K. Sharma, G. Klingelhoefer, and T. Nishida (eds), Wiley STM,doi: 10.1002/9781118714614.ch02