Percy Bysshe Shelley - Poetry Foundation
https://www.poetryfoundation.org/poets/percy-bysshe-shelley
Shelley's page on Poetry Foundation, which contains links to essays, interpretations of his work, and links to his poetry.
The Necessity of Atheism
http://knarf.english.upenn.edu/PShelley/atheism.html
The text of one of Shelley's earliest political and anti-religious writings, "The Necessity of Atheism."
A Defence of Poetry and Other Essays - Project Gutenberg
https://www.gutenberg.org/files/5428/5428-h/5428-h.htm
The text of Shelley's A Defense of Poetry and Other Essays, including "On Love" and "On a Future State."
The Excursion - William Wordsworth
https://archive.org/details/excursionapoem00wordgoog/page/n24
A full-text, interactive edition of Wordsworth's The Excursion.
