Takes one parameter, Source
Description:
Given a row number, returns the corresponding row letter.
This is the inverse of SSColNum$.
Example:
[New] Source = "1"
[New] Source1 = "27"
Source = SSColAlpha$ Source
Source1 = SSColAlpha$ Source1
Html Source 'source is equal to "A"
Html Source1 'source is equal to "AA"