Oriya language
In 1969, Das co-authored with Brajendra Kumar Sethi a high school textbook on Indian history in the Oriya language, entitled "Bharati Bharata Itihasa". It was the first regional language textbook of India to describe the national uprising of 1857 as the "First National Campaign of Independence", rather than following the hitherto accepted phraseology of "Sepoy Mutiny".