Below are reputable sources where you can download comprehensive guides and articles on programming languages in PDF format: Foundational & Comparative Overviews

: Dr. Charles Severance offers his full textbook as a free PDF , which is widely considered one of the best "articles" for beginners starting with Python. Curated Libraries

: While the full book is paid, many chapters on language paradigms and logic are available as PDFs to help you understand how languages work under the hood.