http://www.sec.gov/Archives/edgar/data/73986/000007398618000007/opco424b503-2018.htm
http://www.sec.gov/Archives/edgar/data/1000275/000114036118014194/form424b2.htm
http://www.sec.gov/Archives/edgar/data/1000275/000114036118014259/form424b2.htm
http://www.sec.gov/Archives/edgar/data/1000275/000114036118014264/form424b2.htm
http://www.sec.gov/Archives/edgar/data/1000275/000114036118014267/form424b2.htm
http://www.sec.gov/Archives/edgar/data/1000275/000114036118014269/form424b2.htm
http://www.sec.gov/Archives/edgar/data/1080709/000119312518089346/d554957d424b5.htm
http://www.sec.gov/Archives/edgar/data/1731044/000153949718000465/n1192_424b2-x12.htm