Wordnet 3.0
ADVERB (1)
1. 
 (in formal usage, especially legal usage) for that or for it; 
- Example: "ordering goods and enclosing payment therefor"- Example: "a refund therefor"
The Collaborative International Dictionary of English v.0.48:
Therefor \There*for"\, adv. [There + for. Cf. Therefore.]
   For that, or this; for it.
   [1913 Webster]
         With certain officers ordained therefore. --Chaucer.
   [1913 Webster]
WordNet (r) 3.0 (2006):
therefor
    adv 1: (in formal usage, especially legal usage) for that or for
           it; "ordering goods and enclosing payment therefor"; "a
           refund therefor"