\'On \'Mastering The 21 Immutable Principles Of Brazilian Jiu-Jitsu\', Paulo Guillobel wears a hat of a scholar and proves that, in more than 26 years of practicing, he has not only trained, taught and c.... \'On \'Mastering The 21 Immutable Principles Of Brazilian Jiu-Jitsu\', Paulo Guillobel wears a hat of a scholar and proves that, in more than 26 years of practicing, he has not only trained, taught and c...