1. Homogeneity theorems on perfect codes in Hamming schemes and generalized Hamming schemes, Tokyo J. Mathematics, 8 (1985), 429-438.
  2. An analogue of t-designs in association schemes of alternating bilinear forms, Graphs and Combinatorics, 2 (1986), 259-267.
  3. On nonsymmetric P- and Q-polynomial association schemes, J. Combinatorial Theory, Ser. B 51 (1991), 314-328.
  4. Splitting fields of association schemes, J. Combinatorial Theory, Ser. A 57 (1991), 157-161.
  5. On pseudo-automorphisms and fusions of an association scheme, Europ. J. Combinatorics, 12 (1991), 317-325 (with T. Ikuta and T. Ito).
  6. Amorphous association schemes over the Galois rings of characteristic 4, Europ. J. Combinatorics, 12 (1991), 513-526 (with T. Ito and M. Yamada).
  7. Paires orthogonales de sous-algebres involutives, C. R. Acad. Sci. Paris, Serie I, 314 (1992), 329-331 (with Y. Watatani).
  8. An inequality for primitive translation association schemes, Memoirs Fac. Sci., Kyushu Univ., Ser. A, 46 (1992), 189-194 (with T. Itoh).
  9. A local characterization of the graph of alternating forms, Finite Geometry and Combinatorics, F. De Clerck, et al., editors, 289-302, Cambridge University Press, 1993 (with S. V. Shpectorov).
  10. A local characterization of the graphs of alternating forms and the graphs of quadratic forms over GF(2), Finite Geometry and Combinatorics, F. De Clerck, et al., editors, 303-317, Cambridge University Press, 1993 (with D. V. Pasechnik and S. V. Shpectorov).
  11. The automorphism group and the convex subgraphs of the quadratic forms graph in characteristic 2, J. Algebraic Combin. 2 (1993), 411-419 (with D. V. Pasechnik and S. V. Shpectorov).
  12. Generalized spin models, J. Knot Theory and its Ramifications 3 (1994), 465-475 (with K. Kawagoe and Y. Watatani).
  13. The Terwilliger algebras of group association schemes, Kyushu J. Mathematics 49 (1995), 93-102 (with E. Bannai). preprint version (paper, appendix)
  14. On a class of small 2-designs over GF(q), J. Combinatorial Designs, 5 (1995) 61-77 (with M. Miyakawa and S.Yoshiara).
  15. On perfect t-shift codes in abelian groups, Designs, Codes and Cryptography 5 (1995), 253-259.
  16. An alternative construction of the graphs of quadratic forms in characteristic 2, Algebra Colloquium 2 (1995), 275-287.
  17. On fusion algebras associated to finite group actions, Pacific J. Math., 177 (1997), 269-290 (with H. Kosaki and S. Yamagami).
  18. Orthogonal arrays, primitive trinomials, and shift-register sequences, Finite Fields and Their Applications, 4 (1998), 252-260.
  19. Duality maps of finite abelian groups and their applications to spin models, J. Algebraic Combinatorics, 8 (1998), 223-233 (with Etsuko Bannai).
  20. New 5-designs with automorphism group PSL(2,23), J. Combinatorial Designs, 7 (1999), 147-155 (with M. Kitazume).
  21. Flag-transitive 2-designs arising from line-spreads in PG(2n-1,2), Geometriae Dedicata, 77 (1999), 209-213.
  22. Type IV Self-Dual Codes over Rings, IEEE Trans. Inform. Theory, 45 (1999), 2345-2360. (with S. T. Dougherty, P. Gaborit, M. Harada and P. Sole).
  23. Tight 2-designs and perfect 1-codes in Doob graphs, J. Stat. Planning and Inference, 86 (2000), 505-513 (with J. H. Koolen).
  24. Classification of Type IV Self-Dual Z_4-Codes of Length 16, Finite Fields and Their Applications 6 (2000), 244-254. (with M. Harada).
  25. On Type II codes over F_4, IEEE Transactions on Information Theory, 47 (2001), 2242-2248 (with K. Betsumiya, T. A. Gulliver and M. Harada)
  26. Some results on modular forms --- subgroups of the modular group whose ring of modular forms is a polynomial ring, ``Groups and Combinatorics --- in Memory of Michio Suzuki,'' 245-254, Advanced Studies in Pure Mathematics 32, Mathematical Society of Japan, 2001 (with E. Bannai, M. Koike and J. Sekiguchi).
  27. Type II codes over F_2^r, ``Applied Algebra, Algebraic Algorithms and Error Correcting Codes,'' 2001, Springer Lecture Notes in Comp. Sci. 2227, 102-111 (with Koichi Betsumiya and Masaaki Harada).
  28. A Correction to ``Incidence matrices and finite cyclic projective planes'' by Chat Yin Ho, Des. Codes Cryptogr., 25 (2002), 91--93. (with D. Brozovic and C. Ho).
  29. A mass formula for Type II codes over finite fields of characteristic two, ``Codes and Designs,'' Proceedings of a conference honoring Professor Dijen K. Ray-Chaudhuri on the occasion of his 65th birthday, K. T. Arasu and A. Seress, eds., pp. 207--214, de Gruyter, 2002.
  30. A quasi-symmetric 2-(49,9,6) design, J. Combin. Des., 10 (2002), 173--179 (with Masaaki Harada).
  31. Even unimodular Gaussian lattices of rank 12, J. Number Theory, 95 (2002), 77--94 (with Masaaki Kitazume).
  32. Four-weight spin models and Jones pairs, Trans. Amer. Math. Soc., 355 (2003), 2305--2325 (with Chris Godsil and Ada Chan).
  33. On Hadamard matrices of order 2(p+1) with an automorphism of odd prime order p, J. Combinatorial Designs, 11 (2003), 367--380 (with Daniel B. Dalan and Masaaki Hadara).
  34. Type II codes over F_2 + uF_2 and applications to Hermitian modular forms, Abh. Math. Sem. Univ. Hamburg, 73 (2003), 13--42.
    (with Eiichi Bannai, Masaaki Harada, Tomoyoshi Ibukiyama and Manabu Oura).
  35. Directed strongly regular graphs via coherent algebras, Linear Algebra Appl., 377 (2004), 83--109 (with Mikhail Klin, Mikhail Muzychuk and Paul-Hermann Zieschang).
  36. Spherical 5-designs obtained from finite unitary groups, European J. Combin., 25 (2004), 261--267.

  37. Extremal self-dual $[40,20,8]$ codes with covering radius $7$, Finite Fields and Their Applications, 10 (2004), 183--197 (with Masaaki Harada and Kenichiro Tanabe).

  38. On a $5$-design related to an extremal doubly-even self-dual code of length $72$, J. Combin. Theory, Ser.~A, 107 (2004), 143--146 (with Masaaki Harada, Masaaki Kitazume).

  39. A new quasi-symmetric $2$-$(56,16,6)$ design obtained from codes, Discrete Math., 29 (2004), 231--234 (with Vladimir D. Tonchev).
  40. The nonexistence of certain tight spherical designs, With an appendix by Y.-F.S. P\'etermann, Algebra i Analiz, 16 (2004), 1--23 (with Eiichi Bannai and Boris Venkov).
  41. On some self-dual codes and unimodular lattices in dimension $48$, European J. Combin., 26 (2005), 543--557 (with Masaaki Harada, Masaaki Kitazume and Boris Venkov).
  42. A characterization of designs related to an extremal doubly-even self-dual code of length $48$, Annals of Combinatorics, 9 (2005), 189--198 (with Masaaki Harada, Vladimir Tonchev).
  43. Some restrictions on weight enumerators of singly even self-dual codes, IEEE Trans. Inform. Theory, 52 (2006), 1266--1269 (with Masaaki Harada).
  44. Hyperplane partitions and difference systems of sets, J. Combin. Theory, Ser.~A, 113 (2006), 1689--1698 (with Ryoh Fuji-Hara and Vladimir Tonchev).
  45. On the covering radii of extremal doubly even self-dual codes, Adv. Math. Commun. 1 (2007), 251--256 (with Masaaki Harada).
  46. Simple abelian quadruple systems, J. Combin. Theory, Ser.~A 114 (2007), 1160--1164 (with Masanori Sawa).
  47. Determination of weight enumerators of binary extremal self-dual $[42,21,8]$ codes, Finite Fields and Their Applications, 14 (2008), 177--187 (with Stefka Bouyuklieva and Masaaki Harada).
  48. A new example of non-amorphous association schemes, Contributions to Discrete Mathematics 3, no. 2 (2008), 31--36 (with Takuya Ikuta). (link, magma program)
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