special thanks / grateful acknowledgment (4 episodes, 2009-2011)
special thanks / grateful acknowledgment (4 episodes, 2011-2012)
special thanks (3 episodes, 1998-2003)
special thanks (3 episodes, 2004-2012)
special thanks (3 episodes, 2004-2008)
grateful acknowledgment (3 episodes, 2006-2015)
special thanks / grateful acknowledgment (3 episodes, 2011)
grateful acknowledgment / special thanks / very special thanks (3 episodes, 2011)
special thanks (3 episodes, 2011)
special thanks (2 episodes, 2003)
special thanks (2 episodes, 2004-2008)
special thanks (2 episodes, 2004)
special thanks (2 episodes, 2005-2012)
special thanks (2 episodes, 2005-2006)
special thanks (2 episodes, 2006-2009)
special thanks (2 episodes, 2006-2008)
special thanks (2 episodes, 2006-2007)
special thanks (2 episodes, 2009)
special thanks (2 episodes, 2010)
special thanks (1 episode, 1978)
special thanks (1 episode, 1983)
special thanks (1 episode, 1993)
special thanks (1 episode, 1994)
in memory of (1 episode, 1994)
special thanks (1 episode, 1996)
special thanks (1 episode, 1997)
special thanks (1 episode, 1998)
acknowledgment: archival footage provided by (1 episode, 1998)
thanks (1 episode, 1998)
acknowledgment: archival footage provided by / special thanks (1 episode, 1998)
special thanks (1 episode, 1999)
special thanks (1 episode, 2000)
special thanks (1 episode, 2001)
special thanks (1 episode, 2002)
special thanks (1 episode, 2003)
special thanks: University of Colorado at Boulder (1 episode, 2003)
special thanks (1 episode, 2004)
in memory of (1 episode, 2004)
special thanks (1 episode, 2005)
thanks (1 episode, 2005)
acknowledgment: archive footage provided by (1 episode, 2005)
special thanks (1 episode, 2006)
special thanks (1 episode, 2007)
special thanks: Osaka University (1 episode, 2007)
special thanks (1 episode, 2008)
very special thanks (1 episode, 2008)
in memory of (1 episode, 2008)
special thanks (1 episode, 2009)
special thanks (1 episode, 2010)
special thanks: Southern Illinois University (1 episode, 2010)
special thanks: 7th Earl of Rosse (1 episode, 2010)
special thanks (1 episode, 2011)
thanks (1 episode, 2011)
special thanks (1 episode, 2012)
special thanks (1 episode, 2013)
acknowledgment (1 episode, 2013)
special thanks (1 episode, 2014)
special thanks (1 episode, 2015)
thanks (1 episode, 2015)
special thanks (1 episode, 2019)
thanks (1 episode, 2019)
in memory of (1 episode, 2020)
special thanks (1 episode, 2021)
special thanks (1 episode, 2022)