Ascendit Deus in jubilatione

I have a copy of Liber Cantualis in modern notation that has this chant:

V. Ascendit Deus in jubilatione. R. Alleluia, Alleluia. V. Et Dominus in voce tubae. R. Alleluia, alleluia. V. Gloria Patri… R. Alleluia, Alleluia. V. Sicut… V. Ascendit… R. Alleluia, alleluia.

(This may be a bit off because the typesetting leaves something to be desired.)

Anyway: anyone know where this comes from and where I can get it in square notation?