Planck, [68]

Pope, [219]

Poynting, [68]

Preuner, [311]

Puschin, [222]

Q

Quincke, [52]

R

Rabe, [113]

Ramsay, [3], [22], [23], [24], [30], [32], [63], [64], [66], [79], [90], [165], [178]