Antonín Matějček and Zdeněk Wirth, Modern and contemporary Czech art… (1924)
“ An accent over the vowel ( ́) indicates length:— ú or ůá like the ooa in father. ú or ůé like„ the„ ooa in May. ú or ůí like„ the„ ooee in sheep. ú or ůý like„ the„ ooi in machine. ú or ů like„ the„ oo in doom, cool. A hook over e (ě) softens it into ye; as in Purkyně, pron. Poor-kyn-ye (r) . The primary stress in Czech words always falls on the first syllable. ”
