<human>: I'm a recent college graduate and I'm in the process of looking for a job. I have some work experience (regular jobs/not related to my field) but I want to put couple of my professors down as reference. I emailed them asking would it be okay if I put them down as a reference. Two of the professors wrote back saying they wouldn't mind writing me a RECOMMENDATION LETTER. I can see how professors can be bombarded with phone calls from potential employees of their numerous students hence, the recommendation letter (Get it all done in one shot). The thing is I don't know if they misinterpreted the email and thought I was asking for a recommendation letter or that is the standard protocol among professors.

Does any one know how the professors usually handle reference/recommendation letters? If it's okay for me to put down their office number as reference I want to email them back before they start writing the letter. 
And also, if it's not okay, how would I incorporate something like a recommendation letter into an application?

Can you condense the text into three sentences or less?
<bot>: Is it okay to put down professors office numbers as reference (with permission) or do they only write recommendation letters?