Here are links to the complete online Project Gutenberg texts of works by Johanna Spyri.
::In English::
Mäzli: A Story of the Swiss Valleys
Rico and Wiseli*
*Also sometimes titled Rico and Stineli, and How Wiseli was Provided For
Uncle Titus & His Visit to the Country
What Sami Sings with the Birds
::In German::
Heidi kann brauchen, was es gelernt hat