Algorithm and R implementation: Strona, Giovanni, Domenico Nappo, Francesco Boccacci, Simone Fattorini, and Jesus San-Miguel-Ayanz. 2014. <U+201C>A Fast and Unbiased Procedure to Randomize Ecological Binary Matrices with Fixed Row and Column Totals.<U+201D> Nature Communications 5 (June). Nature Publishing Group: 4114. 10.1038/ncomms5114