Internet Encyclopedia of Philosophy
Internet Encyclopedia of Philosophy: Heraclitus
Excellent introduction to Heraclitus' difficult philosophy from the Internet Encyclopedia of Philosophy. Includes biography relating him to other Ionian and Milesian philosophers. Quotes several of his fragments.
Other
Atlantic Baptist: Pre Socratic Lectures: Empedocles
Lecture notes on the Pre-Socratic philosopher Empedocles from a college philosophy class. Also includes some quotations as well as discussion questions in small rectangles within the notes.
Stanford University
Stanford Encyclopedia of Philosophy: Empedocles
Article about the Greek philosopher Empedocles from the Stanford Encyclopedia of Philosophy. Includes a brief overview of his work and more detailed discussion of his two major works: "On Nature" and "Purifications."
Internet Encyclopedia of Philosophy
Internet Encyclopedia of Philosophy: Parmenides
Good summary from the Internet Encyclopedia of Philosophy of Parmenides' life and thought. Pays special attention to the verse form of his major work, "On Nature."