Generic list of orientations to generate the ideal angles/axes of hcp twins

[Azdiar Gazder]

Dear All,

As you know, twins can be represented using the misorientation angle/axis convention.
However, in the case of hcp materials, the exact misorientation angle varies with the c/a ratio - while the axis remains constant.

With respect to this, I have used the example provided in the following weblinks to generate the angle/axis for one extension twin type for Mg:
https://mtex-toolbox.github.io/files/doc/Misorientations.html
https://mtex-toolbox.github.io/files/doc/TwinningAnalysis.html

The following lines of code work correctly:
cs_hcp = crystalSymmetry('6/mmm', [3.2094 3.2094 5.2108], 'X||a*', 'Y||b', 'Z||c');
T1 = orientation('map',Miller(1,1,-2,0,cs_hcp),Miller(2,-1,-1,0,cs_hcp),Miller(-1,0,1,1,cs_hcp),Miller(1,0,-1,1,cs_hcp))
ideal_angle(T1)/degree
ideal_axis(T1)

The same webpage states:
"...we define first the twinning as a misorientation, which is reported in literature by (1,1,-2,0) parallel to (2,-1,-1,0) and (-1,0,1,1) parallel to (1,0,-1,1)."

My questions are as follows:
1. I am definitely missing something here but even after searching I am unable to find the literature reference from where these orientations have been derived.
2. Would anyone happen to have a ready generic list of orientations that can be inputted into the second line of code - in order to generate the ideal angles/axes for all the other hcp twin systems?
(for example - in keeping with the Mg/Ti examples, the list for orientations that generate the two extension and three compression twin systems)?
3. Alternatively, if no such list exists, can code be written/modified to generate such a list?

Thank you in advance.

Regards,
Azdi