The Carling et al. Paper:
In the peer reviewed research paper published in Clinical Infectious Diseases (2006)(96), Carling et al. showed that only 47% overall of 1,404 high touch objects evaluated at three (3) different hospitals over several months were found to have been cleaned after 2-3 terminal cleanings. However, only 12.3% to 17% of toilet area handholds, bed pan cleaning equipment, and patient room and bathroom door knobs were cleaned. Even more surprising, even after educational interventions with the hospital cleaning staff, 8%, 18%, and 24%, of surfaces in the three respective hospitals tested were still not cleaned. 
The Sitzlar et al. Paper:
A recent peer reviewed study published in "Infection Control and Hospital Epidemiology" shows that 35% of C. difficile (C-Diff.) patient rooms still had viable and detectable residual spores, EVEN AFTER BOTH terminal cleaning by hand AND treatment by UV light, on high touch surfaces.
(“An Environmental Disinfection Odyssey: Evaluation of Sequential Interventions to Improve Disinfection of Clostridium difficile Isolation Rooms”) 
96) Carling et al., “Improved Cleaning of Patient Rooms Using a New Targeted Method”, Clinical Infectious Diseases, 2006; 42:385-8.
3) Sitzlar et al., "An Environmental Disinfection Odyssey: Evaluation of Sequential Interventions to Improve Disinfection of Clostridium difficile Isolation Rooms", Infection Control and Hospital Epidemiology, May 2013, vol. 34, no. 5, pg 459 – 465