. . "Sol" . . "Słońce" . . "Zonnefysica." . . "Espectro solar." . . "Sun" . . . . . . . "An investigation of the rotation period of the sun, by spectroscopic methods"@en . . . . . . . . "An Investigation of the rotation period of the Sun by spectroscopic methods, by Walter S. Adams, assisted by Jennie B. Lasby" . . "An investigation of the rotation period of the sun by spectroscopic methods" . "An investigation of the rotation period of the sun by spectroscopic methods"@en . . . . . . . . . . . "An investigation of the rotation period of the sun by spectroscopid methods" . . . . . . "Rotation period of the sun"@en . "Rotation period of the sun" . . . . .