The first one is very useful as you won't find this kind of information in many articles.. The second one is just an introduction to xml modelling with dtd and schema. But Worth reading once.
Waiting for the the last (5th)article about xml performance & tuning; but they are posting one in 2/3 weeks.
(These articles won't really help you in passing test142 but will give us a great idea of what topics are covered in each section.(ibm 142 objectives page just lists everything))
I bought a voucher for 141 exam . i prepared for that. is it possible to take up 141 exam now?. else we need to take only 142?. please clarify... in scjp now also people are taking 1.4 after they introduced 1.5.