1. Arveson, W., The curvature invariant of a Hilbert module over C[z 1, · · ·, z d], J. Reine Angew. Math., 522, 2000, 173–236.
2. Arveson, W., p-summable commutators in dimension d, J. Operator Theory, 54(1), 2005, 101–117.
3. Arveson, W., Quotients of standard Hilbert modules, Trans. Amer. Math. Soc., 359(12), 2007, 6027–6055.
4. Douglas, R., Essentially reductive Hilbert modules, J. Oper. Theory, 55, 2006, 117–133.
5. Douglas, R. and Sarkar, J., Essentially reductive weighted shift Hilbert modules, J. Oper. Theory, 65, 2011, 101–133.