van Hout HPJ, Nijpels G, van Marwijk HWJ, Jansen APD, Veer PJVan't, Tybout W, Stalman WAB.  2005.  Design and pilot results of a single blind randomized controlled trial of systematic demand-led home visits by nurses to frail elderly persons in primary care [ISRCTN05358495]. BMC geriatrics. 5