The Collaborative International Dictionary of English v.0.48:
Hereof \Here*of"\, adv. Of this; concerning this; from this; hence. [1913 Webster] Hereof comes it that Prince Harry is valiant. --Shak. [1913 Webster]WordNet (r) 3.0 (2006):
hereof adv 1: of or concerning this; "the twigs hereof are physic"