Doppler effect

Fhessnegg, T, S Aggarwal, B Nielsen, Ramamoorthy Ramesh, D.J Keeble, and E.H Poindcxtor. "A study of vacancy-related defects in (pb,la)(zr,ti)o3 thin films using positron annihilation." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 47 (2000) 916–920.

Friessnegg, T, S Aggarwal, B Nielsen, Ramamoorthy Ramesh, D.J Keeble, and E.H Poindexter. "Investigation of vacancy-related defects in (Pb,La)(Zr,Ti)O3 thin films using positron annihilation." IEEE International Symposium on Applications of Ferroelectrics. IEEE, Piscataway, NJ, United States, 1998. 147–150.

Keeble, D.J, S Madhukar, B Nielsen, A Krishnan, P Asoka-Kumar, S Aggarwal, Ramamoorthy Ramesh, and E.H Poindexter. "Vacancy related defects in La0.5Sr0.5CoO3-δ thin films." Proceedings of the Materials Research Society Symposium -. Vol. 477. MRS, Warrendale, PA, United States, 1997. 229–233.