Reference Work is a book or periodical containing facts and information such as dictionaries, encyclopedias, and bibliographies which people can refer to for information across all or specific subject areas. In business valuation analytical work, Reference Works are classified as intangible assets from which exclusive economic benefits accrue to the owners. Intangible assets are a class of assets without physical form (such as a building) which can generate significant value to owners through copyrights to appropriate exclusive rights to the economic benefits. Business valuators apply techniques under the income, market and asset methods to estimate the fair market value of reference works, a situation made possible by the fact that such works can be recognised, separated, and the associated economic benefits can be reliably measured.