Rita Meyer-Spasche has kindly provided a 1993 news clipping featuring Herb - her translation of the article is below. A PDF of the news clipping can be found here.
Münchner Merkur, Weekend issue, 11th/12th September 1993;
Pages with mixed news from Munich
Professor on biking tour
More than 2000 km (1250 miles) were covered on bike until now by Herb Keller (68), professor of applied mathematics and head of the computing center at the Caltech institute in California. The tour led him from Geneva through Innsbruck, Salzburg and Vienna to Prague and Munich, where he also cycled around the Olympic Center. He will go on to Vienna and Budapest. The ultimate destination is England, where he will work for one year, at Cambridge University.