Theo van Doesburg (1920) <i>Klassiek-barok-modern</i>, Antwerpen: De Sikkel, Amsterdam: Em. Querido, [p. 41].
<bdi><a href="https://en.wikipedia.org/wiki/en:Theo_van_Doesburg" class="extiw" title="w:en:Theo van Doesburg"><span title="Dutch architect, painter, draughtsman and writer (1883-1931)">Theo van Doesburg</span></a>
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