I have been watching the Dec13/14 and Dec 14/15 spreads. Just trying to learn how they move, what moves them. Ive noticed over the past few days the Dec 14/15 is weaker than the Dec 13/14 especially today as the 14/15 has broken down ( intraday anyway) while 13/14 is still well in its range. Is there any specific reason for the difference in the moves and does technical analysis of any use on these spreads? If anyone has any articles, blogs or similar related to these kind of spreads I'd be very keen to read some Thanks!