International Phonetic Association, Report on the 1989 Kiel Convention, Journal of the International Phonetic Association, 1989, 19: 67–80, doi:10.1017/S0025100300003868
International Phonetic Association, IPA news, Journal of the International Phonetic Association, 2005, 35 (2): 261–262, doi:10.1017/S0025100305002227
Olson, Kenneth S; Hajek, John, The phonetic status of the labial flap, Journal of the International Phonetic Association, 1999, 29 (2): 101–114, doi:10.1017/S0025100300006484
Olson, Kenneth S; Hajek, John, Crosslinguistic insights on the labial flap, Linguistic Typology, 2003, 7 (2): 157–186, doi:10.1515/lity.2003.014
Olson, Kenneth S; Hajek, John, A crosslinguistic lexicon of the labial flap, Linguistic Discovery, 2004, 2 (2): 21–57
Olson, Kenneth, Mono, Journal of the International Phonetic Association, 2004, 34 (2): 233–238, doi:10.1017/S0025100304001744