Many networks, including collaboration networks like the House committee assignment network, are bipartite (containing two types of nodes, with edges connecting one type to another). This poses many challenges that scientists are still struggling to understand. Here we will endeavor to cite papers that discuss such issues.
M. Latapy, C. Magnien, & N. Del Vecchio, Basic Notions for the Analysis of Large Affiliation Networks / Bipartite Graphs, cond-mat/0611631
Mixture models and exploratory data analysis in networks (Mark Newman and E. A. Leicht)
Generation of complex bipartite graphs by using a preferential rewiring process by Jun Ohkubo, Kazuyuki Tanaka, Tsuyoshi Horiguch.