1. Radiographic detection of fetal numbers in goats;Barker;Can. Vet. J.,1967
2. Obstetric uses of the ultrasonic motion sensor;Bishop;Amer. J. Obstet. Gynaecol.,1966
3. Use of an enzyme immunoassay to determine concentrations of progesterone in caprine plasma and milk;Bretzlaff;J. Am. Vet. Med. Assoc.,1989
4. Ultra-sonographic determination of pregnancy in small ruminants;Bretzlaff;Vet. Med.,1993
5. The use of real-time ultrasound rectally for early pregnancy diagnosis in sheep;Buckrell;Theriogenology,1986