Beatrix Potter's stories can be found in the manuscript picture letters she wrote to children of friends and family members.
Online Exhibitions The Morgan Library & Museum
Beatrix Potter Was a Keen Observer of the Natural World, Smart News
March 4, 1897, page 1, Beatrix Potter: The Picture Letters
See Childhood Sketches of Beloved Illustrator Beatrix Potter at The Morgan - Untapped New York
The Rotunda at the Witching Hour, J. Pierpont Morgan's Library: Building the Bookman's Paradise
Beatrix Potter: The Picture Letters
Beatrix Potter Was a Keen Observer of the Natural World, Smart News
The Morgan Library & Museum
February 4, 1895, page 4, Beatrix Potter: The Picture Letters
Online Exhibitions The Morgan Library & Museum
Victorian Musings: Beatrix Potter: The Picture Letters at The Morgan Library & Museum November 2, 2012-January 27, 2013
The Completed Library, J. Pierpont Morgan's Library: Building the Bookman's Paradise