Error to fetch source of xserver-xorg-video-intel-lts-quantal and get build-deps

[kevin.liu]

OS Image: Ubuntu 12.04.2
I tried to get source of xserver-xorg-video-intel-lts-quantal and get the following errors, please help

1. check which intel driver package installed
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root@stanley:~/Videos# apt-cache policy xserver-xorg-video-intel-lts-quantal
xserver-xorg-video-intel-lts-quantal:
  Installed: 2:2.20.9-0ubuntu2~precise2
  Candidate: 2:2.20.9-0ubuntu2~precise2
  Version table:
 *** 2:2.20.9-0ubuntu2~precise2 0
        100 /var/lib/dpkg/status
2. try to get source of it
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root@stanley:~/Videos# apt-get source xserver-xorg-video-intel-lts-quantal
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to find a source package for xserver-xorg-video-intel-lts-quantal
3. try to get build deps of it
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root@stanley:~/Videos# apt-get build-dep xserver-xorg-video-intel-lts-quantal
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to find a source package for xserver-xorg-video-intel-lts-quantal