High Quality Content by WIKIPEDIA articles! To Come is a printing and journalism reference abbreviated "TK." It is used to signify that additional material will be added at a later date.TK is a combination of letters designed to catch the eye (it is also likely to be caught by computer spell-check programs, though the use of TK long predates the use of computers.) It may originally have come into use because very few words feature the letter combination of "t" followed by "k". The phrase "to come," by contrast, could very easily be mistaken as a deliberate part of the text, especially if read by an overworked editor late at night while on deadline.