Basarir H. Poor, multidimensionally speaking: evidence from South Africa. J Afr Econ. 2011 Jun 1;20(3):463-504. doi: 10.1093/jae/ejr001
Caso P, Sutherland GR, Fleming A, McDicken WN. Doppler tissue imaging: current status and future prospects. G Ital Cardiol. 1995 May 1;25(5):639-47.