Acceptable temperature in a server room?

My boss thinks as long as the temperature in the server room doesn’t go above 80 degrees – everything is fine. I strongly disagree and need backup documentation. The room is about 5 foot by 10 foot and has two servers and a voice mail computer in it. It has no air conditioning and is usally about 80-82 degrees with only a small fan blowing in the room. Can anyone tell me what the safe operating temperature range should be and can you point me to any documentation that I can show him. Many thanks in advance!