3) Josephine Aurnhammer, Harpsichord Sonata in E major
Movt. 1, Allegro Maestoso (1758-1820)
Score: PDF
Paula Maust, Expanding the Music Theory Canon: Sonata, Rondo, Sonata Rondo
Diverse Music Theory Examples: Sonata Form (includes solutions)
Barbara Murphy, Music Theory Materials, "Classical," "Romantic," Baroque." Scan the pages or do a word search to search for specific form types, e.g. "sonata form".
Yale Musical Examples Database: See the "Form" tab at the bottom.