Gawlik, O. 2013. On If and Whether Complement Clauses of ‘See’, ‘Wonder’, and ‘Know’ in Contemporary Spoken Academic American English: A Corpus-Based Study. Respectus Philologicus. 24 (29) (Oct. 2013), 131–141. DOI:https://doi.org/10.15388/RESPECTUS.2013.24.29.11.