The relationship between convergence speed, capital share, and the depreciation rate in the standard Solow growth model is a direct mathematical consequence of its foundational equations, making it common knowledge that requires no citation.
In the standard Solow-Swan growth model, the rate of convergence (often denoted as lambda = (1 - alpha)(n + g + delta), where alpha is the capital share and delta is the depreciation rate) is explicitly a function of the capital share, population growth, technological progress, and the depreciation rate. This is a matter of textbook economic theory and mathematical definition, rendering it common knowledge.