The impact of seed industry concentration on innovation: a study of US biotech market leaders
研究了美国种子行业集中度上升如何降低生物技术研究强度，发现集中度与研究产出相互影响，且受研究结果可占有性和技术机会的影响。
Agricultural research drives increases in agricultural productivity, and the number of private agricultural input firms has been declining. The empirical relationship between the number of firms doing applied biotechnology crop research and the amount of research output they produce is investigated in a research profit function model. Increases in seed industry concentration have reduced biotech research intensity in the United States in the 1990s. Concentration and research are simultaneously determined and are influenced by the appropriability of research results and the state of technological opportunity.