All great examples! Here are some other great researchers/groups that do research in this area:

- Brad Myer's Natural Programming Project at CMU (tons of novel tools!): http://www.cs.cmu.edu/~NatProg/index.html

- Andy Ko's work on debugging and learning to code: http://faculty.washington.edu/ajko/publications

- Emerson Murphy-Hill's work on the usability of dev tools, especially refactoring tools: https://people.engr.ncsu.edu/ermurph3/pubs.html

- Chris Parnin's studies on the cognitive aspects of coding: http://chrisparnin.me/

- Chrsitian Bird's empirical studies of developers: http://www.cabird.com/wp/publications/

- Thomas LaToza's work on the collaborative aspects of development: https://cs.gmu.edu/~tlatoza/papers.html

- Bjorn Hartmann's help support in code editors and tutorial generation: https://people.eecs.berkeley.edu/~bjoern/

- Philip Guo's tools to support novices with coding: http://www.pgbovine.net/publications.htm

- My dissertation "Human-Centric Tools for Navigating Code": http://web.eecs.utk.edu/~azh/publications.html

- Margaret Burnett's work on how people forage for information in code: http://web.engr.oregonstate.edu/~burnett/reprints.html