Regarding you request for source on the "right to invade Gaza": > "Israel will continue to control Gaza's coastline and airspace and reserves the right to undertake military operations when necessary. (Art 3.1)." http://www.mfa.gov.il/mfa/foreignpolicy/peace/mfadocuments/p...
This is also evident by the many incursions Israel has made on Gaza. Israel is still firing shells into Gaza with tanks and mortars! https://www.google.com/search?client=safari&rls=en&q=hundred...
Regarding the Israeli control of Gaza being an occupation:
>In January 2012, the spokesperson for the UN Secretary General stated that under resolutions of the Security Council and the General Assembly, the UN still regards Gaza to be part of the Occupied Palestinian Territory.[15]