The generation of Indo-Europeanists active in the last third of the 20th century, such as Oswald Szemerényi, Calvert Watkins, Warren Cowgill, Jochem Schindler, Helmut Rix, developed a better understanding of morphology and, in the wake of Kuryłowicz's 1956 "L'apophonie en indo-européen", ablaut. Rix's "Lexikon der indogermanischen Verben" appeared in 1997 as a first step towards a modernization of Pokorny's dictionary; corresponding tomes addressing the noun, "Nomina im Indogermanischen Lexikon", appeared in 2008, and pronouns and particles, "Lexikon der indogermanischen Partikeln und Pronominalstämme", in 2014. Current efforts are focused on a better understanding of the relative chronology within the proto-language, aiming at distinctions of "early", "middle" and "late", or "inner" and "outer" PIE dialects, but a general consensus has yet to form. From the 1960s, knowledge of Anatolian began to be of a certainty sufficient to allow it influence the image of the proto-language (see also Indo-Hittite).