lˈaɪ ɡɹˈuːpɔɪdz vˈɜːsᵻz pɹˈɪnsɪpəl bˈʌndəlz ɪn ɡˈeɪdʒ θˈiəɹiz, ɪn pɹəsˈiːdɪŋz ʌvðɪ ˌɪntɚnˈæʃənəl kˈɑːnfɹəns ˌɔn dˌɪfɚɹˈɛnʃəldʒˌiːoʊmˈɛtɹɪk mˈɛθədz ɪn fˈɪzɪks, ˈɛl.ˈɛl. tʃˈaʊ ænd dˈʌbəljˌuː. nˈɑːm, ˈɛdz., plˈɛnəm pɹˈɛs, nˈaɪntiːnhˈʌndɹɪd nˈaɪnti.
Lie Groupoids versus Principal Bundles in Gauge Theories, in Proceedings of the International Conference on Differential-Geometric Methods in Physics, L.-L. Chau and W. Nahm, Eds., Plenum Press, 1990.