[1] All India Inst Med Sci, Bhubaneswar, India
[2] Alexandria Univ, Fac Med, Alexandria, Egypt
[3] Allama Iqbal Med Coll, Lahore, Punjab, Pakistan
[4] King Edward Med Univ, Lahore, Pakistan
[5] Serv Inst Med Sci, Lahore, Punjab, Pakistan
[6] Zagazig Univ, Fac Med, Zagazig, Egypt
[7] Delhi Univ, Kirori Mal Coll, Delhi, India
[8] Andhra Med Coll, Visakhapatnam, Andhra Pradesh, India
[9] All India Inst Med Sci, Dept Internal Med, Jodhpur, India
[10] Imperial Coll London, Royal Brompton Hosp, Natl Heart & Lung Inst, London, England