Long, T.B. and Hanh, T. 2012. Final expression classification based on pseaudo zernike moment invariant, zernike moment invariant, principal component analysis and radial basis function neural network. Journal of Computer Science and Cybernetics. 27, 3 (Apr. 2012), 229–240. DOI:https://doi.org/10.15625/1813-9663/27/3/485.