References
Some of the aliphatic additive constants are based off of this work:
Philip S. Beauchamp, Rodolfo Marquez. A General Approach for Calculating Proton Chemical Shifts for Methyl, Methylene, and Methine Protons When There Are One or More Substituents within Three Carbons
. J. Chem. Ed., 1997, 74(12), 1483-1485.
Some vinylic and aromatic incremental constants, and J constant estimations are based on this textbook:
Friebolin, Horst. Basic One- and Two-Dimensional NMR Spectroscopy.
4th ed. Weinheim: WILEY-VCH Verlag GmbH & Co. KGaA, 2005.
Some vinylic incremental constants are taken from this textbook:
Jackman, L. M. Sternhell, S. Applications of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry.
2nd ed. London: Pergamon Press Ltd, 1969.