https://openforcefield.atlassian.net/wiki/spaces/MEET/pages/1471971345/2021-03-19+WBO+Impropers+meeting+notes
2021-03-19 WBO/Impropers meeting notes - Meetings - Confluence
meeting noteswbomeetingsconfluence
https://www.ks.uiuc.edu/Research/namd/mailing_list/namd-l.2013-2014/0808.html
namd-l: Re: Basic question about impropers
basic questionnamdl
https://openforcefield.atlassian.net/wiki/spaces/MEET/pages/2251391007/2021+WBO+Impropers+meeting+notes
2021 WBO/Impropers meeting notes - Meetings - Confluence
meeting noteswbomeetingsconfluence