Owen, Lindsey (September 3, 2009). "Recession-resistant jobs". Missoula Independent. Archived from the original on August 8, 2010. Retrieved September 9, 2016.
Green, John; Green, Hank (December 31, 2009). VidCon Questions Answered. VidCon. YouTube. Archived from the original on December 21, 2021. Retrieved July 21, 2014.
Hank, Green (July 26, 2013). "Introducing Subbable". vlogbrothers. Archived from the original on December 21, 2021. Retrieved May 21, 2016.
Owen, Lindsey (September 3, 2009). "Recession-resistant jobs". Missoula Independent. Archived from the original on August 8, 2010. Retrieved September 9, 2016.
Green, John; Green, Hank (December 31, 2009). VidCon Questions Answered. VidCon. YouTube. Archived from the original on December 21, 2021. Retrieved July 21, 2014.
Hank, Green (July 26, 2013). "Introducing Subbable". vlogbrothers. Archived from the original on December 21, 2021. Retrieved May 21, 2016.