The contents of the courses here are based on the book "GATEway to Chemical Engineering (set of 5 volumes)" by
M Subbu, D K Sanilya, K Nagarajan, S Siddarth, and R Pavan
(Rishal Publications, Chennai, India)
The questions are predominantly from GATE-CH 2000-2021, and typical questions from other relevant streams of GATE, and other sources.