Holmer, Joan Ozark. "No 'Vain Fantasy':
Shakespeare's Refashioning of Nashe for Dreams and Queen Mab." Shakespeare's Romeo and Juliet: Texts, Contexts, and Interpretation. Ed. Jay L. Halio. Newark: U of Delaware P, 1995. 49-82.

Thesis: Holmer points out that previous to the mid-1590's (when Shakespeare wrote Romeo and Juliet and A Midsummer Night's Dream), fairy-lore did not present tiny fairies as the source of dreams. Holmer then asks why Shakespeare does so, and answers her own question: "The source I propose for considering Shakespeare's imaginative transformations is also markedly original in presenting the first literary association of extremely diminutive spirits and their causitive role in the dreams we mortals have: Thomas Nashe's The Terrors of the Night, or a Discourse of Apparitions (1594)" (50). Holmer then argues this proposition at length, mostly by drawing parallels between Nashe's account of the psychology of dreams and passages in Romeo and Juliet, particularly Mercutio's "Queen Mab" speech. However, in her commentary on Romeo and Juliet, Holmer can think of nothing better than this:

Mercutio's inventive but long-winded tour de force on Queen Mab is not only unnecessary for the forward action of the play, but it actually interrupts the flow of action. Although the impatient Mercutio, a dream-mocker, has just admonished Romeo, a dream-believer, for wasting time, his Queen Mab speech burns daylight even more by bringing the maskers' journey to an absolute standstill so that Benvolio properly concludes they "shall come too late" (1.4.105) to the feast. Might not Mercutio's verse cadenza on Queen Mab, strictly unnecessary for the play's action, be a novel yet complimentary backward glance to the popularity of dream and fairy achieved in A Midsummer Night's Dream?   (69)
If we believe Holmer, Shakespeare was such a careless playwright that he stopped what he was doing so that he could throw in some stuff that had been popular in another play.

Bottom Line: Holmer should have done a better job of explaining why we should care about where Shakespeare got his ideas about fairies and dreams.