Axiomatic theory of sets and classes:
https://drive.google.com/file/d/1XAsout8-FxCY7gxNymTfL3AB8NRPZamY/view?usp=drivesdk
https://www.linkedin.com/in/vahid-mehran-3a145963
https://m.facebook.com/vahi
https://drive.google.com/file/d/1XAsout8-FxCY7gxNymTfL3AB8NRPZamY/view?usp=drivesdk
https://www.linkedin.com/in/vahid-mehran-3a145963
https://m.facebook.com/vahi