Hello Ashish, appreciate you answered my second question in this post and thank you for your time!

I am still confused about the MP entries here. What if the z axis is the strongest material axis? If so, isn't it poisson ratio yz and xz minor ones?

Or say it can only assume in WB MP entries that x is the strongest and not allowed for other axes to be the strongest ones? 

Thank you for your help!

Kind regards!