Useful resources are the Internet Encyclopedia of Philosophy (www.iep.utm.edu/ ) and the Stanford Encyclopedia of Philosophy (plato.stanford.edu/).

There are many online websites that contain the philosophy of religion. Some of these websites include Wikipedia, Philosophy of Religion website, and the Stanford Encyclopedia of Philosophy.

Routledge Encyclopedia of Philosophy was created in 1998.

Because he considers them as units,not numbers

By his definition,units are indivisible in quantity.
(see Aristotle and maths,Stanford encyclopedia of Philosophy)

You can find more information about Aristotle in academic journals and books on philosophy, ancient Greek history, and ethics. Online resources such as Stanford Encyclopedia of Philosophy and Internet Encyclopedia of Philosophy are also great places to learn about Aristotle's ideas and contributions. Additionally, universities and libraries with strong philosophy departments may have dedicated sections on Aristotle's works and influence.