Kamali, M. A.; Böröcz, Z.; Sütő, Z.; Horn, P. Heterosis in Egg Production in Different Parts of the Laying Period of Layers of Rhode Island Red Origin Selected by RRS Selection in Two Environments Part II.: Heterosis in Hen Day Egg Production in Populations under Long Term RRS Selection. AAK 2001, 5 (2), 31-36.