@article {503, title = {A Field-Study of Fertilization and Embryonic Development in the Common Frog (Rana-Temporaria) with Particular Reference to Acidity and Temperature}, journal = {Journal of Applied Ecology }, volume = {28}, year = {1991}, pages = {346-357}, author = {Beattie, R.C. and Aston, R.J. and Milner, A.G.P.} }