Griffiths, PhillipPhillipGriffithsGreen, MarkMarkGreenRobles, ColleenColleenRobles2020-04-232020-04-23https://hdl.handle.net/20.500.12111/7904Working notesI. Introduction II. Extension data for a mixed Hodge structure III. Extension data for limiting mixed Hodge structures IV. Period mappings to extension data (A) V. Period mappings to extension data (B) Appendix to Sections IV and V: Examples VI. Local Torelli conditions VII. Global structure of period mappings from complete surfaces VIII. Period mappings and the canonical bundle Referencesen-USperiod mappingsWorking Paper