Variation of mixed Hodge structure. I. Joseph Steenbrink, Steven Zucker (1985) Inventiones mathematicae
Variations of Abelian Differentials under Quasiconformal Deformations. Yukio Kusunoki, Fumio Maitani (1982) Mathematische Zeitschrift
Variations of (para-)Hodge structures and their period maps in tt*-geometry. Schäfer, Lars (2008) Beiträge zur Algebra und Geometrie