Info found: This book by Bob Ross contains a biography, quotes, and images of his work. Why this source is useful: The link is only a preview of the book, but the biography and other information given is accurate since it's made by his company. The publication is also recent (2017).
Info found: The article shares information about his legacy, and why people enjoy watching his painting show. It talks about the science behind his soothing voice. Why this source is useful: Not many other articles go in-depth when explaining why people watch his show, even though it's a simple concept (he paints something for 20-30 minutes).
Info found: This article shows the behind-the-scenes of Bob Ross' life, and contains the backstory of how his painting show came to be. There are also statements from his manager. Why this source is useful: There are only a few sources that talk about the behind-the-scenes of Bob Ross and "The Joy of Painting", so it's nice to find a website with this information.
Info found: This article contains unique facts about Bob Ross, such as how more than 90% of his viewers don't paint along with him. He also created his own image, and kept up with it despite not liking it anymore. Why this source is useful: There's information supporting the things he did and why he did them.