Symposium paper published in a journal Zhang Y, White CJ, Levin M, Hayward A. 1995. Abstract nr PB0371. Symposium as a whole Ralph CJ, Scott JM, eds. Cerebral cortex tissue cultures. Article in a periodical, electronic full-text Voelker R. 1993.
Scientists still debate the fate of smallpox virus.
Accessed 1996 July 26. Microscopic life unlike any other. Abstract only, original article not seen Furley CW, Tichy H, Uerpmann HP. 1988. Abstract nr 1931. Changes in the structure of the baboon hybrid zone in the Awash National Park, Ethiopia.