U. Michigan (ScienceDaily)
Google - Research database allows searching of the scholarly literature.
Chemistry Dept., U. British Columbia - An excellent, comprehensive set of tutorials on acid/base chemistry, including practice tests.
J. Park, ChemTeam - Extensive tutorials detailing acid base chemistry in historical context.
ChemWorld - A summary of major advances in acid-base research.
An alphabetical glossary of relevant scientific terms.
J. Brønsted - excerpts from his 1923 paper.
S. Sörensen - excerpts from his 1909 paper.
J. Towell, Carroll College - Applet simulates acid titration of a base with multiple acids.