Assessment of ovarian cycles in the African elephant (Loxodonta africana) by measurement of salivary progesterone metabolites

1. Illera, J.-C.
2. Silván, G.
3. Cáceres, S.
4. Carbonell, M.-D.
5. Gerique, C.
6. Martínez-Fernández, L.
7. Munro, C.
8. Casares, M.