There are numerous obituaries, including in The Telegraph and The New York Times.
There are also articles by those who knew and worked with him, including actor Alan Alda and writer Ken Levine:
Larry always sent thank you notes. Larry always dropped you a line wishing you well on your upcoming project. Larry always returned phone calls. Larry always emailed you right back. Larry even left comments on my blog. I half expect a thank you note for this essay.
His legacy will last forever. His work was timeless, universal, steeped in humanity, and brilliant. MASH will always air eight times a night, TOOTSIE and OH GOD! will forever be on your screens (be they 64” plasmas or 2” iPods), FUNNY THING HAPPENED ON THE WAY TO THE FORUM, and CITY OF ANGELS will be revived as long as there are stages...
Enjoy the work of Larry Gelbart. You will laugh until you hurt. And for those of us who were blessed to have known him, we will hurt until we laugh.