In 2001 Gérard’d attended the International Chamber Choir Competition in Marktoberdorf as well as the advanced Choirmasters Seminar.
He was the winner of the Conductor's Prize for Outstanding Artistic Performance at the 6th Harmonie Festival 2011 in Lindenholzhausen, Germany, and the "Pro Musica Viva Maria Strecker Daelen Preis" Conductor's Prize for the Best Interpretation of a Contemporary Choral Work at the 10th International Chamber Choir Competition 2007 in Marktoberdorf, Germany.
Viggo is the main author of the textbook "Mathematical Theory of Domains", Cambridge University Press, 1994 (coauthored by I. Lindström and E. Griffor), and also of a set of Marktoberdorf summer school lecture notes on domain theory.
Fendt tractors, developed and produced in Marktoberdorf are one of the most famous products of the region.
Haberlen has participated as a jury member and auditor in major choral festivals worldwide, including the St. Petersburg Choral Festival, the World Choir in Cardiff, Wales; Marktoberdorf, Germany; Riva del Garda, Italy; Budapest, Hungary; Denmark and Sydney, Australia.