Robuta

https://support.apple.com/en-is/guide/logicpro/lgsife4183a5/mac
The frequency of a sound is known as its fundamental tone.
apple supporttonesharmonicspartials
https://voveo.it/collane/overtones/
overtones
https://www.nicholasmiguel.com/post/exploring-overtones-by-whistling
You can see that the resonances of your formants line up with the overtones of your sound by using vocal fry alongside the sung note (this trick is discussed...
exploringovertoneswhistling
https://www.themoscowtimes.com/2017/06/09/russias-oil-bargin-with-iran-is-probably-politically-motivated-a58173
Russia and Iran have signed a major oil-for-goods swap in a move that signals strengthening ties between the countries.
russiaoilbargainiranpolitical
https://archive.org/details/overtonesfiftiet1974curt/page/n104
Contemporary photographs by George Krause.
the curtisovertonesanniversaryissueinstitute
https://www.theovertones.co.uk/
The Overtones - Rocking out of Sussex since 2006 - not a close vocal harmony group
the overtonesfor agood timerocking