Looking for "Great Rivers of the World" series by Newsweek Books

I am currently reading The River Congo, a very good book. It was originally published in 1977 by Newsweek, Inc. On the copyright page it notes that it is part of the Newsweek Books' Great Rivers of the World Series. However, in spite of searches of Amazon, LT, Google, Ask, Ebay and Wikipedia I have been unable to find a list of other books of the series, or even a single additional book. Does anyone have information on this series?