E: Package acroread has no installation candidate
 

Я новичок.При инсталяции PDF Readerа ($ sudo apt-get install acroread) возникает ошибка:Reading package lists... DoneBuilding dependency tree Reading state information... DonePackage acroread is not available, but is referred to by another package.This may mean that the package is missing, has been obsoleted, oris only available from another sourceE: Package acroread has no installation candidateЮзал поиск - везде старые репозитарии.Дайте пожалуйста ссылку на рабочии репозитарии или скажите че делать.