1. Ache, A. and Chang, S. Y. A., Sobolev-trace inequalities of order four, 2015. arXiv: 1509.06069v1
2. Beckner, W., Sharp Sobolev inequalities on the sphere and the Moser-Trudinger inequality, Ann. of Math. (2), 138(1), 1993, 213–242.
3. Branson, T. P., Sharp inequalities, the functional determinant, and the complementary series, Trans. Amer. Math. Soc., 347(10), 1995, 3671–3742.
4. Case, J., Boundary operators associated to the Paneitz operator, 2015. arXiv: 1509.08347
5. Case, J., Some energy inequalities involving fractional GJMS operators, 2015. arXiv: 1509.08342