Existing in a variety of forms, the quatrain appears in poems from the poetic traditions of various ancient civilizations including Ancient India, Ancient Greece, Ancient Rome, and China; and, continues into the 21st century, where it is seen in works published in many languages.
I always thought that Mgr. refers to a manager and that's what you find in dictionaries as well. People in Czech use it to stress the fact they are the boss:) Magistr does apply to Master, as in Master's degree, and short versions are M, MAS, or mstr.
The R with a little accent over it is a distinct sound unique to the Czech language. It is made by touching the tip of the tongue to the roof of the mouth and then by blowing air you let the tongue slap against the palate a few times. Children need to practice this sound as part of their language lessons.