Documents affecting Woburn real estate, such as deeds and mortgages, if properly prepared and legally acceptable, are recorded at the South Middlsex County Registry of Deeds in chronological order and assigned a book and page number. They are then indexed by grantor, grantee, document type and address. The documents affecting a particular piece of property are searched, analyzed and examined by a party seeking to determine the legal status of the ownership rights in the property. This status is referred to as the title to the property. In Middlesex County, the title search is usually done by a trained examiner or attorney hired by the buyer or buyer's lender. Registered land comprises about twenty percent of the property in Middlesex County. Under this system (sometimes referred to as the "Torrens" system) the Massachusetts Land Court has adjudicated and decreed the status of the title. Thereafter, subsequent owners of registered land are issued numbered certificates describing the property and noting any encumbrances (such as mortgages) or rights affecting the property. Documents filed in the registered section are assigned document numbers, not book and page numbers. The criteria for filing documents affecting registered land are much stricter than those affecting recorded land.