I am looking at output for REG procedue.

I don't understand the difference betweenSquared Semi-partial corrType IandSquared Semi-partial Type II

and likewiseSquared Partial CorrType IandSquared Partial CorrType II.

I understand the difference between partial and semipartial correlation. I just don't get "Type I" and "Type II". Where do they come from and what are they for/what do they do? But really I just need to know which one is the right one to use? I want to draw a venn diagram.