SPELLING OF -ING AND -ED FORMS OF VERBS ENDING IN -IC, -AC. The Columbia Guide to Standard American English. 1993

Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.

SPELLING OF -ING AND -ED FORMS OF VERBS ENDING IN -IC, -AC


Panic, picnic, traffic, and other verbs whose infinitives end in -ic add a k before putting on a further inflection or suffix: panicked, panicking, picnicked, picnicking, trafficked, trafficking, etc. Bivouac does the same: bivouacking, bivouacked.	1