T. Dwyer, Scalable, Versatile and Simple Constrained Graph Layout, Proceedings of the 11th Eurographics / IEEE -VGTC Conference on Visualization, pp.991-1006, 2009.
DOI : 10.1111/j.1467-8659.2009.01449.x
URL : http://www.csse.monash.edu.au/~tdwyer/Dwyer2009FastConstraints.pdf

S. Murai and T. Ushiama, Review-based recommendation of attractive sentences in a novel for effective browsing, International Journal of Knowledge and Web Intelligence, vol.3, issue.1, pp.58-69, 2012.
DOI : 10.1504/IJKWI.2012.048164

. Statista, Number of bookstores in the u.s. 2017. https://www.jpoksmaster