Rujukan Regurgitasi (pencernaan)

  1. ↑ Nelson, R.W. and C. G. Couto. Small Animal Internal Medicine, 4th ed. 2009.
  2. ↑ Keeling, Linda K.; Gonyou, Harold W. (2001). Social behaviour in farm animals. CABI Publishing. m/s. 69. ISBN 0-85199-717-1.
  3. ↑ Loon, Rael; Loon, Hélène (2005). Birds: the inside story. Struik Publishers. m/s. 183. ISBN 1-77007-151-2.