- Author: John Hubbard, Barbara Burke Hubbard
- Language: English
- Year: 2015
- Author: John Hubbard, Barbara Burke Hubbard
- Language: English
- Year: 2015
- Author: John H. Hubbard, Barbara Burke Hubbard
- Language: English
- Year: 2009
- Author: Barbara Burke Hubbard (auth.)
- Language: German
- Year: 1997
- Author: Barbara Burke Hubbard
- Language: English
- Year: 1997
- Author: Barbara Burke Hubbard
- Language: English
- Year: 1996
- Author: Barbara Burke Hubbard John H. Hubbard
- Language: English
- Year: 1998
- Author: John Hamal Hubbard Barbara Burke Hubbard
- Language: English
- Year: 1998