The first link is about a lull that was supposed to have been agreed to AFTER the barrage of rocket attacks from Hamas. It has nothing to do with who broke the initial ceasefire. The claim from the UN official is that Israel broke this new 48 hour truce, not the original one.
The second link talks about the violations of the truce which took place in November. First Israel raided those tunnels in Gaza as I mentioned, and then Hamas responded by launching a bunch of rockets at Israel. It notes that after both violations, the ceasefire was most likely going to be reinstated. These incidents in November came several months after the initial violations in June when rockets were launched at Israel a few days after the truce was agreed to.
Your third link is an interview with a Palestinian representative on CNN citing the November incident and then the CNN news anchor reads some printouts from US News and World Report and other news sites that mention that November incident.
Israel did not believe that incident was a violation of the truce since they claimed they were preventing an imminent attack, which they reserved the right to do as part of the agreement.
In any case, Hamas responded to Israel's actions with a rocket barrage against Israel.
So they both broke it, and then both went back to observing it, and then Hamas officially ended it.
Incidentally, here's an article from June about that initial violation from The Washington Post:
Gazan Rockets Threaten Truce
JERUSALEM, June 24 -- Palestinian fighters lobbed rockets into southern Israel on Tuesday, jeopardizing a six-day-old truce in and around the Gaza Strip.
http://www.washingtonpost.com/wp-dyn/content/article/2008/06/24/AR2008062400616.html