Marius Tico, Pauli Kuosmanen. Weighted least squares method for the approximation of directional derivatives. In IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2001, 7-11 May, 2001, Salt Palace Convention Center, Salt Lake City, Utah, USA, Proceedings. pages 1681-1684, IEEE, 2001. [doi]
Abstract is missing.