at senescence.info
You can search for any reference by title, author, date, editor, journal and publisher. Searching is case insensitive, and allows for only partial terms (e.g. seq with pickup both RNA-Seq and sequencing) matching. You can also use advanced queries that are detailed here.
Willen et al. (1991) "Patterns of glycosaminoglycan/proteoglycan immunostaining in human skin during aging." J. Invest. Dermatol. 96(6):968-974 (PubMed)