How L*ab conversion occurring in MATLAB

I recently converted some color images to L*ab colour space in matlab, using the default function provided (applycform) in MATLAB.

later from some genuine sources (<http://www.easyrgb.com/index.php?X=MATH&H=02#text2>) i understood several modes are there to convert RGB images to L*ab color space, like we can select some observer angle and Illuminant type. And selecting different types we will get different values for L*ab.

So my doubt is what kind of transformation is standard and what type MATLAB uses in its default function used for conversion?

[KAE]

Stephen's answer here may help.

[KALYAN ACHARJYA]

Check here