Introducing an efficient sampling method for national surveys with limited sample sizes: application to a national study to determine quality and cost of healthcare. - Parsaeian, Mahboubeh; Mahdavi, Mahdi; Saadati, Mojdeh; Mehdipour, Parinaz; Sheidaei, Ali; Khatibzadeh, Shahab; Farzadfar, Farshad; Shahraz, Saeid (BMC Public Health, 2021)