This is a (not necessarily complete) list of articles that I've started or to which i've contributed to "significantly" at some point. Therefore I (still) feel some sort of editorial responsibility for them.
Mathematics edit
Moulton plane, de Gua's theorem, Intercept theorem, Simplex, Albrecht Beutelspacher, Percy Heawood, Morrie's law, Theodor Schneider, Aida Yasuaki, Yoshida Koyu, Japanese theorem for concyclic polygons, Japanese theorem for concyclic quadrilaterals, Wada Nei, Kambei Mori, Takebe Kenko, linear space,Joseph Leonard Walsh, Hanfried Lenz,Steiner-Lehmus theorem,Rule of Sarrus, William Wallace, Varignon's theorem,Fagnano's problem, Pizza theorem,Shannon multigraph, Albert Leon Whiteman Memorial Prize, Partial linear space, Harro Heuser, George Phillips Odom, Jr, Dinostratus' theorem, C. L. Lehmus, Jordan's inequality, Steve Selvin, Geometric mean theorem, Anne's theorem, Newton's theorem (quadrilateral), Quadratrix of Hippias, Thomsen's theorem, Gerhard Thomsen, Pappus' area theorem, Eduard Lill, Finsler-Hadwiger Theorem, Victor Thébault, Gerhard Christoph Hermann Vechtmann, Kurt Schiffler, Euler's quadrilateral theorem, Intersecting chords theorem, Intersecting secants theorem, Tangent-secant theorem, Commandino's theorem, Weitzenböck's inequality, Constant chord theorem, Johannes Tropfke, Theorem of the gnomon, Van Schooten's theorem, Pompeiu's theorem, Carnot's theorem (perpendiculars), Carnot's theorem (conics), Karl Gustav Reuschle, Reuschle's theorem, Maxwell's theorem (geometry), Exsymmedian, Fuhrmann circle, Fuhrmann triangle, Wilhelm Fuhrmann, Clawson point, equal detour point, Sylvester's triangle problem, Median triangle, Parbelos, Hooper's paradox, Vivanti-Pringsheim theorem, Chessboard paradox, Candido's identity, Midpoint theorem (triangle), Midpoint theorem (conics), Eyeball theorem, Soddy line, Bevan point, Cauchy's limit theorem, Griffiths' theorem, Pedal circle, Taylor circle, Conway circle theorem
Geography edit
Amazon River, Wetter_(river), Weil River, Nidda River, Knüll, Kleiner Feldberg, Konosha, Teles Pires, Bode River, Thuringia, Parima Mountains, Opolje, Forte Principe da Beira, Mundo (river), Hausberg (Taunus), Lake Waiau, Ostrong, Böddiger Berg, Wingsbach (Ahr)
Miscellaneous edit
Akira Yoshimura, Hisako Matsubara, Matsubara Naoko,Ruth Bonner, Nymphaea colorata,Ponte di Quintodecimo,Antigone of Troy,Grzimek's Animal Life Encyclopedia,Jupiter Barrier,José Sentis,John Rutherford (professor),Aula Palatina, Gripenberg Castle,Der Landser, Hsu Feng,Nonja (Vienna), Rainbow Shiner, Papias (admiral), Battle of Lake Constance, Marcus Junkelmann, Mattium, Diana Veteranorum, Li Ji (archeologist), Knights of the Hare, Trabea, Whoonga, Daniel Starch, Gur Sikh Temple, Julian Bennett (archeologist), Susanne Graf,Pink lady (cocktail), Kleiner Klebeband, Schloss Wolfegg, Wolfegger Kabinett , Maximilian Willibald of Waldburg-Wolfegg, Noémi Kiss, Thomas Hagan, Sicilian orange salad, The Last Word (cocktail), Fauziah Ibrahim, Gidara, Peacock Clock, Yasutake Funakoshi, TIM (firm), Shunsuke Matsumoto, Urca de Lima, Backfischroman, Hydrolagus melanophasma, Alan Snow, Jean Bernard Bossu, Herman ze German, Robin Anderson, Arthur Nightingale, Cigdem Akyol, Douglas (parrot), Leïla Slimani, Pascale Hugues, Neopalpa donaldtrumpi, Deborah Feldman, Dietrich Schwanitz, Lederstrumpfbrunnen, Christina Chong, Johann Adam Hartmann, Abigail Lawrie, Julia Shaw (psychologist), Othman Slimani, Lottehaus, La Mamounia literary award, Battle of the Eclipse, Malichus II, Laetitia Coryn, Catherine Amy Dawson Scott, Otto Follmann, Imogen Waterhouse, Braid (film), Emily Cox (actress), George Spahn, Emma Becker, Eva Killutat, Julius Licinus, Kalle Saksela, Catherine Văn-Davies (actress), Kaori Muraji, Über den Wolken,Ariane Müller, Frank Joseph Fogarty