BT BQ 70a(10) :כל אורכתא דלא כתיבא ביה זיל דון וזכי ואפיק לנפשך לית בה מששא‏ : every power of attorney in which is not written "go to court, prevail, and take it out yourself," is not valid
See the entire entry for ˀwrkh#2 n.f. power of attorney for debt collection