Here is the CMT Uptime check phrase
PUBLICATIONS

A Comparison of Mail and E-mail for a Survey of Employees in U.S. Statistical Agencies

Couper, Mick P; Blair, J; Triplett, T. (1999). A Comparison of Mail and E-mail for a Survey of Employees in U.S. Statistical Agencies. Journal of Official Statistics. 15(1), 39-56.