A New Approach to the Synthesis of 2-Methyl-4H-furo[3,2-c][1]benzopyran-4-ones and 2H,5H-Pyrano[3,2-c][1]benzopyran-5-ones - Kumar, R Jagdish; Krupadanam, G L David; Srimannarayana, G (Synthesis, 1990)