“…Unilateral and self-contact problems, such as those of the form considered in Ciarlet & Nečas [1985, 1987, have been further studied, notably in Baiocchi, But-Downloaded 02/20/22 to 44.224.250.200 . Redistribution subject to SIAM license or copyright; see https://epubs.siam.org/terms-privacy xviii Preface to the Classics edition (Volume I) tazzo, Gastaldi & Tomarelli [1988], Gwinner [1989], Schuricht [2002], Habeck &Schuricht [2006], andDvorsky &Gwinner [2009].…”