Poetry in the post-war period followed a number of interlinked paths, most notably deriving from surrealism (such as with the early work of René Char), or from philosophical and phenomenological concerns stemming from Heidegger, Friedrich Hölderlin, existentialism, the relationship between poetry and the visual arts, and Stéphane Mallarmé's notions of the limits of language. Another important influence was the German poet Paul Celan. Poets working within these philosophical/language concerns—especially concentrated around the review "L'Ephémère"—include Yves Bonnefoy, André du Bouchet, Jacques Dupin, Claude Esteban, Roger Giroux and Philippe Jaccottet. Many of these ideas were also key to the works of Maurice Blanchot. The unique poetry of Francis Ponge exerted a strong influence on a variety of writers (both phenomenologists and those from the group "Tel Quel"). The later poets Claude Royet-Journoud, Anne-Marie Albiach, Emmanuel Hocquard, and to a degree Jean Daive, describe a shift from Heidegger to Ludwig Wittgenstein and a reevaluation of Mallarmé's notion of fiction and theatricality; these poets were also influenced by certain English-language modern poets (such as Ezra Pound, Louis Zukofsky, William Carlos Williams, and George Oppen) along with certain American postmodern and "avant garde" poets loosely grouped around the language poetry movement (such as Michael Palmer, Keith Waldrop and Susan Howe; with her husband Keith Waldrop, Rosmarie Waldrop has a profound association with these poets, due in no small measure to her translations of Edmond Jabès and the prose of Paul Celan into English).