While Duggal is the gold standard, do not let the lack of his PDF stop your learning. Consider these authoritative alternatives available legally online:
This article explores the content of the book, its key features, and how to effectively use it for exam preparation. punjabi grammar by narinder singh duggal pdf
Master the Ling-Bachan (Gender-Number) agreement and the Kriya di Kirat (Verb forms). If you master those two chapters from Duggal’s book, you will have conquered 70% of Punjabi grammar. While Duggal is the gold standard, do not