Current information systems model enterprises that are crisp. A crisp enterprise is defined as one that is highly quantifiable; all relationships are fixed, and all attributes are atomic valued. This paper is based on precise enterprises, where data are imperfect and where multiple and possibly conflicting sources of information do exist. Imperfection may be related to the actual values or the time that something happened within an organisation. In such domains different sources of information may be assigned different degrees of reliability. Factual imperfection and/or temporal indeterminacy may cause uncertainty. Temporal information may be recurring, periodical or definite. This paper is presenting a conceptual and algebraic framework for a uniform treatment and representation of all these types of information.