Sánchez D A
J Math Biol. 1980 Jun;9(4):361-8. doi: 10.1007/BF00276499.
A population growth is modelled by the Von Foerster PDE with accompanying Lotka-Volterra integral equation describing the birth rate; the age specific death and fertility rates are assumed to depend only on age and not time. A harvesting policy where a fraction of the population of age greater than a given age is harvested for a fraction of a given season. This introduces a time dependence, but this difficulty is circumvented by devising approximate time-independent models whose birthrates bracket the true birthrate--the standard renewal equation theory applies to the approximate models so quantitative results can be obtained.
人口增长由冯·福斯特偏微分方程建模，并伴有描述出生率的洛特卡 - 沃尔泰拉积分方程；假设年龄特异性死亡率和生育率仅取决于年龄而非时间。一种捕捞策略是在给定季节的一部分时间内捕捞年龄大于给定年龄的一部分人口。这引入了时间依赖性，但通过设计近似的与时间无关的模型来规避这一困难，这些模型的出生率界定了真实出生率——标准更新方程理论适用于这些近似模型，因此可以获得定量结果。
