Not my first publication, but my first one with some challenging engineering. I did this in my late teens and it was published in a hobby electronics magazine, "Electronics Australia". https://adrianfreed.com/content/audio-oscillator-using-digital-ics

I discovered by accident that some folk from Greece published the same ideas in a professional technical journal in 1989 (attached). If you are a scholar of such things it is interesting to compare and contrast the modes of articulation in my vernacular engineering approach with those of the academic paper.