Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Relational database:

"

In 1974, IBM began developing System R, a research project to develop a prototype RDBMS.[3][4] The first system sold as an RDBMS was Multics Relational Data Store (June 1976).[5][6][citation needed] Oracle was released in 1979 by Relational Software, now Oracle Corporation.[7] Ingres and IBM BS12 followed. Other examples of an RDBMS include IBM Db2, SAP Sybase ASE, and Informix. In 1984, the first RDBMS for Macintosh began being developed, code-named Silver Surfer, and was released in 1987 as 4th Dimension and known today as 4D.[8]