The manuscripts are extremely fragmentary, no two of them following quite the same conventions, and these marks may represent the individual reader's aide-memoire rather than a formal system of punctuation (for example, vowel signs are often used only where the word would otherwise be ambiguous). In one manuscript, presumably of somewhat later date than the others, there are separate marks for different conjunctives, actually outnumbering those in the Tiberian system (for example, "munach" before "etnachta" has a different sign from "munach" before "zaqef"), and the overall system approaches the Tiberian in comprehensiveness. In some other manuscripts, in particular those containing Targumim rather than original text, the Tiberian symbols have been added by a later hand. In general, it may be observed that the Palestinian and Tiberian systems are far more closely related to each other than either is to the Babylonian.