1. Campbell, D. M. (1988a). Physiological changes and adaptation: Weight gain. In I. MacGillivray, D. M. Campbell, & B. Thompson (Eds.), Twinning and twins (pp. 101-102). New York: John Wiley & Sons.
2. Campbell, D. M. (1988b). Physiological changes and adaptation: Nutrition and metabolism. In I. MacGillivray, D. M. Campbell, & B. Thompson (Eds.), Twinning and twins (pp. 102-103). New York: John Wiley & Sons.
3. Campbell, D. M. (1988c). Physiological changes and adaptation - blood and cardiovascular changes. In I. MacGillivray, D. M. Campbell, & B. Thompson (Eds.), Twinning and twins (pp. 103-107). New York: John Wiley & Sons.
4. Campbell, D. M. (1988d). Physiological changes and adaptation - renal, respiratory and liver function. In I. MacGillivray., D. M. Campbell, & B. Thompson (Eds.), Twinning and twins (pp. 108-109). New York: John Wiley & Sons.