TY - JOUR AU - D. van Blerkom BT - The Astrophysical Journal DA - Jan-06-1968 DO - 10.1086/149609 PY - 1968 EP - 963 T2 - The Astrophysical Journal TI - The Effect of Diffuse Ionizing Radiation in Collisionally Excited Nebulae UR - http://adsabs.harvard.edu/full/1968ApJ...152..963V VL - 152 SN - 0004-637X ER -