Not long ago a reviewer of Wilson Follett's Modern American Usage quoted from that book as a sample of its "good advice" a declaration concerning adverbs. "The belief that adverbs should end in -ly is hard to down in the mistaken purist, and one often meets the tone of reprobation about the short forms. A newspaper will comment quizzically on the public authorities that have given outright approval to road-signs like 'Drive Slow.' "
Foley, L. (1969). Just Who is the "Mistaken Purist"?. Reading Horizons: A Journal of Literacy and Language Arts, 10 (1). Retrieved from https://scholarworks.wmich.edu/reading_horizons/vol10/iss1/2