arxiv ref: 1405.4259Title: The O($\alpha_s^3 T_F^2$) Contributions to the Gluonic Operator Matrix ElementAuthors: J. Ablinger, J. Bluemlein, A. De Freitas, A. Hasselhuhn, A. von Manteuffel, M. Round, C. SchneiderNode: DESYSupervisor: BluemleinWork Packages: WP3: ToolsMilestones: M3.3.4 Consistent PDF fits at NNLO