Mark-and-Recapture is a methodology from Population Biology to estimate the population of a species without counting every individual. This is done by multiple samplings of the species using traps and discounting the instances that were caught repeated. In this paper we show that this methodology is applicable for bibliographic analysis as it is also not feasible to count all the relevant publications of a research topic. In addition this estimation also allows us to propose a stopping rule for researchers to decide how far one should extend their search for relevant literature.