Allopathic impact of some medicinal plants on Portulaca oleracea L. and Lepidium sativum L. seed germination: a study to find natural herbicide - Fattahi, M; Fattahi, B; Seyed Shirazi, S; Mosavi, F; Moharram Zade, M; Nazeri, V (Planta Medica, 2011)