How to calculate planform adjustmentfactors?

[Igwe Aneke]

To include a correction for finite AR wings and 3-dimensional airflow , Andy Lennon's book 'The Basics of RC Model Aircraft Design' incorporates two graphical ways of determining the planformadjustmentfactors for aspect ratio and taper ratio.
Eventhough this manner works fine, I would like to be able to just calculate these factors. Does anyone know the formula's for achieving this?
And the formula's for calculating the adjustmentfactors for the induced drag of a wingplanform?

[Ollie]

See:
http://aero.stanford.edu/WingCalc.html
It includes twist, AR, AoA and induced drag. It is a better way of wing design tool.
Also:
http://ciurpita.tripod.com/rc/rcsd/drag/drag.html

[Igwe Aneke]

Thanks for the links Ollie. I actually already knew the first one :o , but thanks again! :D