| http://www.w3.org/ns/prov#value | - The method of claim 13, wherein the viscoelastic surfactant is selected from the group consisting of:(a) an amine having to the formula ##STR14## (b) an amine salt having the formula ##STR15## and (c) a quaternary ammonium salt having the formula ##STR16## wherein R1 is an aliphatic group having at least 16 carbon atoms which may be branched or straight chained and which may be saturated or unsatu
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