Skottfelt, J., Bramich, D. M., Jaimes, R. F., Jorgensen, U. G., Kains, N., Harpsoe, K. B. W., et al. (2013). EMCCD photometry reveals two new variable stars in the crowded central region of the globular cluster NGC 6981 (vol 553, A111, 2013). Astronomy and Astrophysics, 558: C1. doi:10.1051/0004-6361/201321430e.