Uchida, M., Ishizaka, K., Hansmann, P., Kaneko, Y., Ishida, Y., Yang, X., Kumai, R., Toschi, A., Onose, Y., Arita, R., Held, K., Andersen, O. K., Shin, S., & Tokura, Y. (2011). Pseudogap of Metallic Layered Nickelate R₂₋ₓSrₓNiO₄ (R = Nd, Eu) Crystals Measured Using Angle-Resolved Photoemission Spectroscopy. Physical Review Letters, 106(027001). https://doi.org/10.1103/physrevlett.106.027001