FRAN ALEXANDER , PETER BLAIR , JOHN DAINTITH , ALICE GRANDISON , VALERIE ILLINGWORTH , ELIZABETH MARTIN , ANNE STIBBS , JUDY PEARSALL , and SARA TULLOCH "UDF ." The Oxford Dictionary of Abbreviations. . Encyclopedia.com. (November 21, 2024). https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/udf

FRAN ALEXANDER , PETER BLAIR , JOHN DAINTITH , ALICE GRANDISON , VALERIE ILLINGWORTH , ELIZABETH MARTIN , ANNE STIBBS , JUDY PEARSALL , and SARA TULLOCH "UDF ." The Oxford Dictionary of Abbreviations. . Retrieved November 21, 2024 from Encyclopedia.com: https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/udf

JOHN DAINTITH "UDF ." A Dictionary of Computing. . Encyclopedia.com. (November 21, 2024). https://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/udf

JOHN DAINTITH "UDF ." A Dictionary of Computing. . Retrieved November 21, 2024 from Encyclopedia.com: https://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/udf