KEJŽAR, Nataša, 2005, Analysis of U.S. patents network: development of patents over time. Advances in methodology and statistics [online]. 2005. Vol. 2, no. 2, p. 195–208. [Accessed 14 April 2025]. Retrieved from: http://mrvar.fdv.uni-lj.si/pub/mz/mz2.1/kejzar.pdf