Although somewhat dated, this PDF of FAQ of German Hum sufferers shows the extent of the problem and contains information which is still relevant and some may find of interest
http://www.igzab.de/download/IGZAB_FAQ_Print_EN.pdf -- You received this message because you are subscribed to the Google Groups "Hum Sufferers" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hum-sufferers?hl=en.
