BOYER, S. W.; 						RYAN, E. L.; 						SPENCER, S. F..
 Biological assessment of the effects of a hog confinement farm on the North Skunk River in central Iowa.
<strong>Tillers</strong>, [S.l.], v. 5, p. 5-8, june 2012.
Available at: &lt;<a href="../../view/38.html" target="_new">https://ojs.grinnell.edu/index.php/tillers/article/view/38</a>&gt;. Date accessed: 12 oct. 2021.