From "LA DISCOGRAPHIE DU ROCK FRANCAIS" by Francis Grosse Y Bernard Gueffier:
"How to kiss the Sky" is the first trace of Claude ENGEL on record before he became a member of MAGMA. OMEGA PLUS is the group formed by Claude ENGEL who is not content just to play - and very well too - guitar or flute but also gives a very good show as a vocalist. Released in '69, OMEGA PLUS's album was influenced by CREAM but its music also contains a foretaste of MAGMA on the B side which features a long piece full of electric energy, folly and a frenzied rhythmic beat. Claude ENGEL gives a fabulous display of his talent as a guitarist on this track.

From " Scented Gardens Of The Mind" by Dag Asbj?rnsen:
This trio led by Claude Engel made a legendary album . Just 1,000 copies were pressed in 1969. Side one had 5 short songs with English lyrics, ranging from heavy progressive blues-rock to largely acoustic songs (comparable to Cream and Blind Faith). Claude Engel's voice is also quite similar to Jack Bruce's. The other side had a long live track named "Voyelles", based on a poem by Arthur Rimbaud, including a recitation. This is the primal scream of "zeuhl" rock, in a very raw and rudimentary form that quite a few will interpret as vaguely planned three man jamming. Overall the album is undoubtedly historical, but not entirely satisfying for all that.