López, K., Heida, M., Jonker, P., Torres, M., Roberts, T., Walton, D., …Harrison, F. (2020). NIR Counterparts to ULXs (III): Completing the photometric survey and selected spectroscopic results*. Monthly Notices of the Royal Astronomical Society, 497(1), 917-932. https://doi.org/10.1093/mnras/staa1920