Binary Optimal Linear Rate 1/2 Codes. - Koichi Betsumiya; T. Aaron Gulliver; Masaaki Harada (AAECC, 1999)

Type II Codes over F2r. - Koichi Betsumiya; Masaaki Harada; Akihiro Munemasa (AAECC, 2001)

Binary Optimal Odd Formally Self-Dual Codes. - Koichi Betsumiya; Masaaki Harada (Des. Codes Cryptogr., 2001)

Classification of Formally Self-Dual Even Codes of Lengths up to 16. - Koichi Betsumiya; Masaaki Harada (Des. Codes Cryptogr., 2001)

On type II codes over F4. - Koichi Betsumiya; T. Aaron Gulliver; Masaaki Harada; Akihiro Munemasa (IEEE Trans. Inf. Theory, 2001)

Formally Self-Dual Codes Related to Type II Codes. - Koichi Betsumiya; Masaaki Harada (Appl. Algebra Eng. Commun. Comput., 2003)

Extremal Self-Dual Codes over F2 × F2. - Koichi Betsumiya; T. Aaron Gulliver; Masaaki Harada (Des. Codes Cryptogr., 2003)

On self-dual codes over some prime fields. - Koichi Betsumiya; Stelios Georgiou; T. Aaron Gulliver; Masaaki Harada; Christos Koukouvinos (Discret. Math., 2003)

Type II codes over F2m+uF2m. - Koichi Betsumiya; San Ling; Fidel R. Nemenzo (Discret. Math., 2004)

Jacobi forms over totally real fields and type II codes over Galois rings GR(2m, f). - Koichi Betsumiya; YoungJu Choie (Eur. J. Comb., 2004)

Optimal self-dual codes over F2*F2 with respect to the Hamming weight. - Koichi Betsumiya; Masaaki Harada (IEEE Trans. Inf. Theory, 2004)

Ozeki Polynomials and Jacobi Forms. - Koichi Betsumiya; YoungJu Choie (Ars Comb., 2005)

Codes over F4, Jacobi forms and Hilbert-Siegel modular forms over Q(sqrt(5)). - Koichi Betsumiya; YoungJu Choie (Eur. J. Comb., 2005)

Minimum Lee weights of Type II codes over I. - Koichi Betsumiya (Discret. Math., 2008)

Mass Formula for Even Codes over. - Koichi Betsumiya; Rowena Alma L. Betty; Akihiro Munemasa (IMACC, 2009)

Hadamard matrices of order 32 and extremal ternary self-dual codes. - Koichi Betsumiya; Masaaki Harada; Hiroshi Kimura (Des. Codes Cryptogr., 2011)

A Complete Classification of Doubly Even Self-dual Codes of Length 40. - Koichi Betsumiya; Masaaki Harada; Akihiro Munemasa (Electron. J. Comb., 2012)

On triply even binary codes. - Koichi Betsumiya; Akihiro Munemasa (J. Lond. Math. Soc., 2012)