Are these three lines from "Lieder" references to songs, too?
In the song Lieder, Adel Tawil references in almost each line a (usually popular) song.
The German Wikipedia article about this song lists the references in a table. However, three lines are missing a reference:
from the refrain:
Und ich singe diese Lieder,
from the third strophe:
Ich sang nur noch für mich,
für ’ne unendlich lange Zeit.
Are these references, too?
I don't think these are quotes from songs. The first quote just means "And I am singing these songs." The second quote is a reference to the time between the end of his boy band The Boyz and the founding of Ich+Ich with Annette Humpe. It translates to:
I only sang for myself
for an infinitely long time
Then it continues "und dann traf ich auf sie", that is "and then I met her" meaning Annette. It then continues with lines taken from Ich+Ich songs.