Topic summaryΘ Expand Summary Extracted from the Wikipedia article Theta. References^ .^^.^, ϴ,φ,ϴ,φ angle, angular displacement, angular separation, rotation angle^.^^^^^^^ 224. ISBN . As a consequence, the critical level for joining shifts from θ to θ' -...^^ . Ways of Proof Theory: 7–30. doi:10.1515/9783110324907.7.^.^^^.^^^.^ 276. JSTOR 20190914.^ 457.^ .^ . Wikipedia source