Terms sourced from: http://iupac.org/publications/pac/80/2/0059/

"Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008)", Harris, R.K.;Becker, E.D.;Cabral De Menezes, S.M.;Granger, P.;Hoffman, R.E.;Zilm, K.W., Pure And Applied Chemistry 2008, 80(1), 59