The book by Gonda is his Change and continuity in Indian religion, with an article ‘The number sixteen.’ As I remember well he also discusses other numbers.
Veroffentlichungen der Glasenapp-Stiftung 44
Siegfried Lienhard:
Kleine Schriften
Edited by Oskar von
Hinuber, 2008
page 159-173
and in:
Langue, style et structure dans le monde Indian, Paris, 1996, 523-536