You should use whichever reference indicator is applicable. In the example you've attached, I would think the UEB reference indicator would be appropriate - but I would need to see how you transcribed it to know for sure. If you are within Nemeth switches, use the Nemeth reference indicator. If you are outside the Nemeth switches, use UEB reference indicators. BE SURE that the indicator used within the text matches the one used with the actual note at the bottom of the print page in braille.