You wish to gain 30 days Premium on sympto.org: for a moment, you become our ambassador for some useful work
1) You leave a positive message on Google Play or the AppStore and you copy your text into your message box.
2) You send 4 sponsor-E-Mails (always 4 at the time) and you tell us on your message box that you have done it (there is not automatic release and your contacts are not obliged to open a sympto account): our counselor will switch on your 30 days Premium. In addition, you will receive a sympto booklet in pdf.
Don't forget to tell your friends about this mail before or, better, once you have sent it.