Hybridized discontinuous Galerkin method with lifting operator. - Issei Oikawa (JSIAM Lett., 2010)

Discontinuous Galerkin FEM of hybrid type. - Issei Oikawa; Fumio Kikuchi (JSIAM Lett., 2010)

Remarks on numerical integration of $L^1$ norm. - Takahito Kashiwabara; Issei Oikawa (JSIAM Lett., 2013)

A Hybridized Discontinuous Galerkin Method with Reduced Stabilization. - Issei Oikawa (J. Sci. Comput., 2015)

Analysis of a Reduced-Order HDG Method for the Stokes Equations. - Issei Oikawa (J. Sci. Comput., 2016)

Penalty Method for the Stationary Navier-Stokes Problems Under the Slip Boundary Condition. - Guanyu Zhou; Takahito Kashiwabara; Issei Oikawa (J. Sci. Comput., 2016)

Penalty method with P1/P1 finite element approximation for the Stokes equations under the slip boundary condition. - Takahito Kashiwabara; Issei Oikawa; Guanyu Zhou (Numerische Mathematik, 2016)

An HDG Method with Orthogonal Projections in Facet Integrals. - Issei Oikawa (J. Sci. Comput., 2018)

The Crouzeix-Raviart element for the Stokes equations with the slip boundary condition on a curved boundary. - Guanyu Zhou; Issei Oikawa; Takahito Kashiwabara (J. Comput. Appl. Math., 2021)

A non-overlapping Schwarz algorithm for the HDG method. - Issei Oikawa (CoRR, 2023)