Sources introduces the Atlas Trio, a new group led by the French clarinettist Louis Sclavis, and is his ninth album for ECM. Clarinet, piano and electric guitar meet without bass or drums, in music that moves between chamber improvisation, polyrhythmic grooves, minimal pulse patterns and free group playing. It is an open-form record, exploratory in its means and direct in its effect, with a cast that was new to Sclavis's work on the label.

Sclavis plays clarinet and bass clarinet, Benjamin Moussay piano, Fender Rhodes and keyboards, and Gilles Coronado electric guitar. The album was recorded in September 2011 at Studios La Buissonne in Pernes-les-Fontaines, in the south of France, with Gérard de Haro as engineer and Manfred Eicher as executive producer. Eight pieces are new compositions by Sclavis. Outside Of Maps is credited to all three musicians, and the closing Sous influences is by Coronado. In an interview with Jazz Magazine quoted by ECM, Sclavis described music "conceived for this group and which couldn't exist until we'd played it".

The opening Près d'Hagondange sets precise, written lines for clarinet and piano against looser improvisation, with Moussay's low register entering at the climaxes. On Dresseur de nuages his Fender Rhodes lays a droning bed under Coronado's processed guitar. A Road To Karaganda is quieter and modal, Sclavis's clarinet lines floating over wide piano textures, and the title track adds a light programmed beat to the trio sound. Quai sud frees Coronado from rhythm duties for a duet with the clarinet, and La Disparition gives Sclavis's bass clarinet its most forceful moment.

Steve Mossberg reviewed the album for The Free Jazz Collective in June 2012. He compared Coronado's move to the foreground on Quai sud to "a shift made with the accuracy and sensitivity of a top-class second violinist". He placed some pieces in ECM's world-chamber idiom, yet judged that Sources "is well worth a listen or ten". Covering a June 2012 concert in Berlin for London Jazz News, Sebastian Scotney noted the new personnel and observed that Sclavis keeps an element of surprise in each project. On ECM Reviews, Tyran Grillo heard affinities with the trio work of Anouar Brahem.

CD edition, ECM 2282, first released on 25 May 2012.