Table - link
||Robbins, Clarence R. Interactions of Shampoo and Creme Rinse Ingredients with Human Hair, pp.122-170, chapter 5 in the book Chemical and physical behavior of human hair / Clarence R. Robbins.-2nd ed (2002) p.159 table 5-9
|| Jacinto Steinhardt, Charles H. Fugitt, and Milton Harris, Further investigations of the affinities of anions of strong acids for wool protein, Part of Journal of Research of the National Bureau of Standards, Volume 2 February 1942 pp.201-216 link  Vickerstaff, R. "The Physical Chemistry of Dyeing," p 373, Interscience, NY (1954)
||Primary source  abstract: "Titration curves of wool with 18 strong acids at 0°, 25°, or 50° C have been added to the data for 19 others presented earlier. Several have been investigated at more than one temperature. The reversibility of the equilibria measured has been demonstrated quantitatively. New anion-wool dissociation constants, based on modifications of equations previously used to calculate anion-wool affinities, are tabulated for 33 anions, and heats of dissociation of a few anion-wool complexes are also given. The previously reported tendency of affinity to rise with molecular-weight is confirmed: fairly consistent relationships between the affinity and the molecular weights of strong organic acids appear."
||P.158 bottom paragraph: "Table 5-9 illustrates anion affinities of several acids [primary source 110] and shows that simple anions like chloride and ethyl sulfate have very low affinities for keratin, whereas surfactant anions, such as dodecyl sulfate or dodecyl sulfonate, and dye anions have relatively high affinities. In fact, the anion affinities of Table 5-9 show a correlation (r = 0.94 and r^2 = 0.90) with molecular weight, suggesting that 90% of the variance can be explained by molecular weight. Since most of these anions differ primarily by increasing size of either aliphatic or aromatic substituents, this type of affinity may be associated with Van der Waals interactions. Therefore, the decreasing hydrophilic nature and increasing keratinophilic nature of these organic acids with molecular size cause the acid to partition from the aqueous phase to the keratin phase."