Some early work of Thomas Henry published as an Electronics "Designer's Casebook" design idea.
"Low Frequency VCO Gives Exponential Response," Thomas Henry. Pdf: https://www.proaudiodesignforum.com/ima ... 3_1983.pdf

"Low Frequency VCO Gives Exponential Response," Thomas Henry, Electronics, January 13, 1983.
Related content:
"Electronic Music Generator Retriggers Waveforms," Thomas Henry, Electronics, November 30 1981.: https://www.proaudiodesignforum.com/for ... 698&p=7960