@inproceedings {beech-spp-2004,
	title = {Periodicity in a Penna model},
	booktitle = {Proceedings of the 22nd Samahang Pisika ng Pilipinas Physics Congress},
	year = {2004},
	month = {25{\textendash}27 Oct 2004},
	pages = {11},
	address = {Bohol Tropics Resort, Tagbilaran City},
	abstract = {<div>A population of an asexually reproducing species is simulated using a suggested 8-bit string length implementation and a modified implementation of the Verhulst factor. The age structure of the population generated by this implementation is found to be non-Gompertzian and time-dependent. The change in age structure is shown to be a result of the periodic behavior of the population of its component ages, with relatively similar period, but different phase.</div>},
	author = {Maria Donna N Beech and Ronald S. Banzon}
}