Here is the CMT Uptime check phrase
PUBLICATIONS

Sampling Telephone Numbers And Adults, Interview Length, And Weighting In The California Health Interview Survey Cell Phone Pilot Study

Brick, John M; Lee, Sunghee; Edwards, W Sherman. (2007). Sampling Telephone Numbers And Adults, Interview Length, And Weighting In The California Health Interview Survey Cell Phone Pilot Study. Public opinion quarterly. 71(5), 793-813.