Meanwhile, Microsoft began introducing its most prominent office products. Microsoft Works, an integrated office program which combined features typically found in a word processor, spreadsheet, database and other office applications, saw its first release as an application for the Apple Macintosh towards the end of 1986. Microsoft Works would later be sold with other Microsoft products including Microsoft Word and Microsoft Bookshelf, a reference collection introduced in 1987 that was the company's first CD-ROM product. Later, on August 8, 1989, Microsoft introduced its most successful office product, Microsoft Office. Unlike the model of Microsoft Works, Microsoft Office was a bundle of separate office productivity applications, such as Microsoft Word, Microsoft Excel and so forth. While Microsoft Word and Microsoft Office were mostly developed internally, Microsoft also continued its trend of rebranding products from other companies, such as Microsoft SQL Server on January 13, 1988, a relational database management system for companies that was based on technology licensed from Sybase.