https://books.google.it/books?id=WuBhMmMK6BAC&pg=PA147&lpg=PA1 | Elettrone Libero

https://books.google.it/books?id=WuBhMmMK6BAC&pg=PA147&lpg=PA147&dq=mind+thoughts+are++square+waves&source=bl&ots=SEK1H8FV1V&sig=ACfU3U32Nvw5uqtGxBsgQ8bVvmst0g9kKw&hl=it&sa=X&ved=2ahUKEwj6mOn_vv33AhWJQ_EDHQSCCZMQ6AF6BAgqEAM#v=onepage&q=mind%20thoughts%20are%20%20square%20waves&f=false