Works by the French painter Caroline Coppey appear in PSA 14 and Extinctions, and Bleu jour is based on the work of the same artist. The poems Gréan has addressed to the general work of Luisa Gardini, Caroline Coppey and Giorgio Bevignani are in à.
Gréan has also enjoyed collaborating with artists. 80 is an artist's book with a lithograph by Luisa Gardini, an Italian artist who also contributed to Mai, Monstres tièdes, corps et riens, Successions, à, Rideau and Sonnets des satiétés; Gardini also turned Monstres tièdes into a book of her own, WPMT15, published by cythère critique in 2005 (), as well as a series of bookmarks published by Ecbolade in 2004, and a poster stamped by atelier de l'agneau in 2003.