1. Granlund, G.H.: In search of a general picture processing operator. Computer Graphics and Image Processing 8, 155–173 (1978)
2. Bigün, J., Granlund, G.H.: Optimal orientation detection of linear symmetry. In: Proceedings of the First IEEE International Conference on Computer Vision, London, pp. 433–438. IEEE Computer Society Press, Los Alamitos (1987)
3. Kass, M., Witkin, A.: Analyzing oriented patterns. Computer Vision, Graphics and Image Processing 37, 362–385 (1987)
4. Knutsson, H.: Producing a continuous and distance preserving 5-d vector representation of 3-d orientation. In: IEEE Computer Society Workshop on Computer Architecture for Pattern Analysis and Image Database Management, Miami Beach, Florida, pp. 175–182 (1985)
5. Knutsson, H.: Representing local structure using tensors. In: The 6th Scandinavian Conference on Image Analysis, Oulu, Finland, pp. 244–251 (1989)