When you remove glue down linoleum, the backing usually seperates and sticks to the subfloor.  Therefore, it is not easy to reuse glue down linoleum.  I recommend buying some matching linoleum.  To remove the old linoleum, pull off the linoleum which usually leave the baking stuck to the glue on the subfloor.  Apply some Krud Kutter to the area, let sit 1 minute (be careful to keep it from getting under the linoleum that you plan to keep).  After a minute, use a scraper to remove the backing and adhesive.  Then install new linoleum.