http://books.google.com/books?id=gHrzgo0ghfMC&pg=PA237&lpg=PA237&dq=%22block+trader+strategy%22&source=bl&ots=pYNpd1goNd&sig=WJ6smYlPcsRG7vHmAnzh8B4CXuM&hl=en&ei=HaNQS-WTE4KIswPtx92CCA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA#v=onepage&q=%22block%20trader%20strategy%22&f=false