Three eggs in a clutch of the Nightjar. - M.V. Matantseva, S.A. Simonov. - Berkut. 20 (1-2). 2011. - P. 110.
A clutch with three eggs was found in Olonets district of Karelia (NW Russia) in July 2011. [Russian].
E-mail: mariamatantseva@gmail.com.