CUSUM : Hawkins DM, Olwell DH (1997) Cumulative sum charts and charting for
quality improvement. Springer-Verlag New York. ISBN 0-387-98365-1 p 47-74

Gan FF (1994) Design of Optimal Exponential CUSUM Charts. Journal of Quality Technology 26:2 p. 109-124. Program
code in Fortran available at url = http://lib.stat.cmu.edu/jqt/26-2

Gan FF and Choi KP (1994) Computing Average Run Lengths for Exponential CUSUM Schemes. Journal of Quality Technology
26:2 p. 134-143