I found the web page information useful in the top part of the page. The bottom part of the page involving exposure calculation is available in many other places.
I do own and use the meter and I am able to estimate exposure quite well without the meter. Sometimes I do not carry the meter when I use camera without meter or with bad meter (selenium cell meter, meter that requires mercury battery etc.) then I would estimate exposure. With that said, I do use my meters very often but I rather estimate the exposure without a meter than using a questionable meter.