Hayes introduces two basic rules of stress assignment (foot formation): the English Stress Rule (ESR) and Strong Retraction Rule (SRR). The ESR applies at the right edge of the word, assigning maximally binary feet labeled S W, where W may not be a heavy syllable (not counting "extrametrical" material). The SRR applies iteratively from right to left, also assigning maximally binary feet labeled S W, but without restrictions as to syllable weight. [...] The ESR [...] applies regardless of whether the string is already provided with a metrical organization or not. The SRR, on the other hand, strictly repects existing metrical structure.
- Kiparsky (2004), a pag.141