Mathematica commands to produce combined QSO FP planes in 3/4 view:

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$TextStyle = {FontFamily -> "Times"};

g = Plot3D[78.1 - 1.94 m + 7.88 r, {m, -10, 40}, {r, -1, 2}, 
      MeshStyle -> {RGBColor[1, 0, 0]}];

f = Plot3D[78.1 - 4 m + 10r, {m, -10, 40}, {r, -1, 2}, 
      MeshStyle -> {RGBColor[0, 0, 1]}];

Show[%, %%, AxesLabel -> {mu_e, log r_e, log L_x}, 
    PlotLabel -> FontForm["QSO FPs", {"Times-Bold", 18}]];

Export["qsofp_test.pdf", %, "PDF"];

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Mathematica commands to produce Principal Axes in oblate spheroid form:
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ParametricPlot3D[{{0.60 Sin[t], 0.35 Cos[t], 0}, {0, 0.35 Sin[t], 
      0.05 Cos[t]}, {0.60 Sin[t], 0, 0.05 Cos[t]}}, {t, 0, 2Pi}, 
  AxesLabel -> {"e2", "e1", "e3"}, AspectRatio -> Automatic]

ParametricPlot3D[{0.60 Cos[t] Cos[u], 0.35 Sin[t]Cos[u], 0.05Sin[u]}, {t, 0, 
    2Pi}, {u, -Pi/2, Pi/2}, AxesLabel -> {"e2", "e1", "e3"},
  LightSources -> {{{-0.6, -0.3, 0.2}, RGBColor[1, 1, 0]}, {{0.6, 0.3, 0.15}, 
        RGBColor[1, 0, 1]}}]

Show[%, %%]
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