Я удалю эту строку в sources.list?

Эта строка deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic main restricted, Строка 63, в sources.list не известна на sudo apt-get update и заставляет Синаптический Диспетчер пакетов и Центр программного обеспечения Ubuntu отказывать. Действительно ли безопасно удалить эту строку?

Мой sources.list похож на это:

# deb cdrom:[Xubuntu 14.04.1 LTS _Trusty Tahr_ - Release amd64 (20140723)]/ trusty     main multiverse restricted universe

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ utopic main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://us.archive.ubuntu.com/ubuntu/ utopic-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ utopic universe
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic universe
deb http://us.archive.ubuntu.com/ubuntu/ utopic-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ utopic multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic multiverse
deb http://us.archive.ubuntu.com/ubuntu/ utopic-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ utopic-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-backports main restricted universe multiverse

deb http://us.archive.ubuntu.com/ubuntu/ utopic-security main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-security main restricted
deb http://us.archive.ubuntu.com/ubuntu/ utopic-security universe
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-security universe
deb http://us.archive.ubuntu.com/ubuntu/ utopic-security multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu utopic partner
deb-src http://archive.canonical.com/ubuntu utopic partner

## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu utopic main
deb-src http://extras.ubuntu.com/ubuntu utopic main
deb http://us.archive.ubuntu.com/ubuntu/ utopic-proposed main restricted universe multiverse
# deb-src cdrom:[Xubuntu 14.04.1 LTS _Trusty Tahr_ - Release amd64 (20140723)]/     trusty main multiverse restricted universe

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic main restricted
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates main restricted
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic universe
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic universe
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates universe
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic multiverse
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates multiverse
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-backports main restricted universe multiverse
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-backports main restricted universe multiverse

deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-security main restricted
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-security main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-security universe
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-security universe
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-security multiverse
deb-src-src http://us.archive.ubuntu.com/ubuntu/ utopic-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb-src http://archive.canonical.com/ubuntu utopic partner
deb-src-src http://archive.canonical.com/ubuntu utopic partner

## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb-src http://extras.ubuntu.com/ubuntu utopic main
deb-src-src http://extras.ubuntu.com/ubuntu utopic main
deb-src http://us.archive.ubuntu.com/ubuntu/ utopic-proposed main restricted universe multiverse