Pantoja, S., D.J. Repeta, J.P. Sachs, and D.M. Sigman. 2002. “Stable Isotope Constraints on the Nitrogen Cycle of the Mediterranean Sea Water Column”. Deep-Sea Research Part I: Oceanographic Research Papers 49: 1609-21. doi:10.1016/S0967-0637(02)00066-3.

Sigman, D.M., P.J. Difiore, M.P. Hain, C. Deutsch, Y. Wang, D.M. Karl, A.N. Knapp, M.F. Lehmann, and S. Pantoja. 2009. “The Dual Isotopes of Deep Nitrate As a Constraint on the Cycle and Budget of Oceanic Fixed Nitrogen”. Deep-Sea Research Part I: Oceanographic Research Papers 56: 1419-39. doi:10.1016/j.dsr.2009.04.007.