6Jaitly V K, Jain P K. Estimation of trace of acid content of bitumen by potentiometic titrations. Bull Electrochem, 19862(2) :205-206
7Ryszard Heropolitaski, Aleksandra Oburska, Janusz Lamparski. A simplified method for determining the acidity of mineral oils. Nafta (Katowice, Pol), 1977, 33(6): 204-206
8Minkova Z A, Bebaev Ⅵ, Maslova O M. Potentiometric determination of acid numbers of colored products of paraffin oxidation. Khim Prom-st, Ser: Metody Anal. Kontrolga Kach Prod Khim Prom-sti, 1981, (3): 18-20
9Semukhina G V, Prusenke V V. Potentiometric method of determining the acid number of mineral oils. Khim. Prom-st,Ser: Metody Anal Kontrolga Kach Prod Khim Prom-sti,1979, (10): 22-23
10BS 2000: Part 213-1993 Determination of neutralization value of bitumen-color indicator titration method
