What to Do When a Prospective Client Doesn't Respond to Your Proposal
http://www.usabilityprofessionals.org/upa_publications/upa_voice/volumes/2005/august/proposal_response.html

Benun, Ilise
Usability Professionals Association
2005

Abstract:

These days, it seems to be the way more and more very busy people are simply saying 'Not right now.' So what do you do about it? Do you leave the ball in their court and just sit around waiting for them to hit it back? Of course not.