solid+contents
81Allotropes of oxygen — Contents 1 Atomic oxygen 2 Dioxygen 3 Singlet oxygen 4 Ozone …
82High-intensity focused ultrasound — Contents 1 Theory 2 Aiming 3 How HIFU works 4 Method of use …
83Staunton Gambit — a b c d e f g …
84Sokolsky Opening — a b c d e f g …
85Masking (in art) — Contents 1 In painting 1.1 Solid masks 1.2 Liquid masks 2 …
86Dutch Defence — a b c d e f g …
87Chess middlegame — a b c d e f g h …
88Outpost (chess) — Contents 1 Notes …
89Los Alamos chess — a b c d e f …
90Connected pawns — a b c d e f g h …