First Example of Ionic Liquids-Promoted Domino Knoevenagel Hetero-Diels-Alder Reactions: A Facile Synthesis of Pyrano[3,2-c]coumarins - Yadav, J S; Reddy, B V S; Naveenkumar, V; Rao, R Srinivasa; Nagaiah, K (Synthesis, 2004)