I created the soundscape to this video from samples taken from the wikipedia file at https://en.wikipedia.org/wiki/File:Gradual_chant_-_Universi_qui_te_expectant.ogg a recording of the plainchant "Universi qui te expectant, with thanks and acknowledgement to members of Schola Antiqua.
I believe that the original file is a work licensed under the Creative Commons Attribution-ShareAlike 3.0 License.