400. That’s an error.

Google cannot redirect you to http://www.chegg.com/textbooks/the-mythical-man-month-2nd-edition-9780201835953-0201835959?c_id=sem&preSelection=buy&utm_source=google&utm_medium=cpc&utm_campaign=tb--long_tail-googleshopping because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.