1. T. Ito, K. Tanabe, P. Terwilliger, Some algebra related to P- and Q-polynomial association schemes, Codes and Association Schemes (Piscataway NJ, 1999) 56 (2001) 167–192.
2. Two linear transformations each tridiagonal with respect to an eigenbasis of the other;Terwilliger;Linear Algebra Appl.,2001
3. Two relations that generalize the q-Serre relations and Dolan-Grady relations;Terwilliger,2001
4. Leonard pairs from 24 points of view;Terwilliger;Rocky Mountain J. Math.,2002
5. P. Terwilliger, Two linear transformations each tridiagonal with respect to an eigenbasis of the other: the TD-D and the LB-UB canonical form, preprint.