When citing the Bayley Scales of Infant Development in APA format, you would include the author (Nancy Bayley), the publication year (1969), the title of the test (Bayley Scales of Infant Development), the edition (i.e., 3rd edition), and the publisher (Psychological Corporation). An example citation would be: Bayley, N. (1969). Bayley Scales of Infant Development (3rd ed.). Psychological Corporation.