Laudého, Y., & Fraud, J.Y. 1970 [A method of estimating the populaion of P. blanchardi occurring in date plantations.]. Fruits 25(4): 247-251.

Notes: [Original title: Une methode d'estimation de la population de P. blanchardi Targ. presente sur le dattier. English summary p. 303.] This method is also recommended for Unaspis citri.