THE FERTILITY OF PROLIFIC BREEDS (FINNSHEEP, ROMANOV SHEEP, EAST FRIESIAN MILKSHEEP) AND THEIR CROSSES WITH MUTTON MERINO V. JAKUBEC and J. KRIZEKGenet. Sel. Evol., 9 1 (1977) 123-124DOI: https://doi.org/10.1051/gse:19770131