Does each LOR have to be written on official letterhead? For example, let's say one reference does not want to be contacted at work but can be contacted at home. Is it ok if that reference does not use company letterhead but instead just types a letter showing his home address? In that case, what should be written on the AADSAS application regarding this reference's business affiliation and address? i.e., On the AADSAS application, is it ok to leave business affiliation blank and list the home address, or is it ok to list the company name but then list the home address for the address? Thanks.