Opposing Open Source?

Carl Nasal asks: "For a college class I'm taking, I have to write a research paper. I chose a topic of how open source software affects businesses, focusing on the use of Linux. While doing searches, I have actually found it hard to find opposing views of open source software. Mainly, what I'm looking for, are opinions, articles, looks, and evidence about the drawbacks of using open source software in business. They can either be online or offline, but preferably from reliable sources. (In other words, I'd rather not just have someone's homepage that loves Microsoft and hates Linux.)" The more constructive criticism we get about the drawbacks of Open Source, the better we can address and fix them.