'Two population studies by the Conservation Society reprinted from ... "Conservation News". No.56, dated June, 1975'.
The twilight of parenthood / [by] John Guillebaud. The elderly in a stationary or declining population / [based on a longer article by Jane Pink] by John Guillebaud. ISBN 0903127105. Published by Conservation Society in 1976. Publication and catalogue information, links to buy online and reader comments.