RT Journal Article SR Electronic T1 Similar proportions of patients developed pressure ulcers on alternating pressure overlays and alternating pressure mattresses JF Evidence Based Nursing JO Evid Based Nurs FD BMJ Publishing Group Ltd and RCN Publishing Company Ltd SP 22 OP 22 DO 10.1136/ebn.10.1.22 VO 10 IS 1 YR 2007 UL http://ebn.bmj.com/content/10/1/22.abstract AB