Formula for calculating self resonant frequency of secondary coil or helical coil?

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Original poster: "Mercurus2000 by way of Terry Fritz <teslalist-at-qwest-dot-net>" <mercurus2000-at-cox-dot-net>

Hello everyone, I was just curious, I know there are programs out there 
that calculate the self resonant frequency of a secondary coil, like 
wintesla etc. But does anyone know the actual equation the programs use? I 
would like to know so I would be able to find the frequencies without 
having to use a computer and the like