For the shorthand formula of fatty acids, in the spec, it gives an example on the side which is like octadec-9,12-anoic acid, 18,2(9,12) but in the OCR text book it said "two numbers separated by a colon" and for the same compound it said the shorthand notation would be 18:2(9,12)..... so would you follow the spec or the book? and when I googled it, it was separated by a colon