Apologies from the cross post but Jeff Zorn posted this on Ancmed and, knowing the love of all things hoplite her, thought it might be of interest.
Oxford Journal of Archaeology
Volume 35, Issue 2 Pages 123 - 221, May 2016
http://onlinelibrary.wiley.com/doi/10.1111/ojoa.v35.2/issuetoc?campaign=woletoc (http://onlinelibrary.wiley.com/doi/10.1111/ojoa.v35.2/issuetoc?campaign=woletoc):
'Twas When my Shield Turned traitor'! Establishing the Combat Effectiveness of the Greek Hoplite Shield (pages 197-212) Kevin Rowan De Groote Article first published online: 25 APR 2016 | DOI: 10.1111/ojoa.12085
Alas, I suspect you need some sort of academic access or deep pockets to get to it but someone might be able to look at it.
Well, one can view the article (http://onlinelibrary.wiley.com/doi/10.1111/ojoa.12085/epdf?r3_referer=wol&tracking_action=preview_click&show_checkout=1&purchase_referrer=onlinelibrary.wiley.com&purchase_site_license=LICENSE_DENIED) but cunningly all pages except the first are blurred beyond readability. However with some careful refocussing in the vicinity of the conclusion one can perceive that the author is very favourably impressed with the aspis as a means of protection.