1Graff M, Thacher TD, Fischer PR, Stadler D, Pam SD, et al (2004) Calcium absorption in Nigerian children with rickets. Am J Clin Nutr 80: 1415-21.

2 Nutritional Surveillance Project (2001) Rickets in Bangladeshi children: a small focus or a widespread problem? Bull. Helen Keller International, Bangladesh.

3Lerch C, Meissner T (2007) Interventions for the prevention of nutritional rickets in term born children. Cochrane Database Syst Rev: CD006164.

4Akpede GO, Solomon EA, Jalo I, Addy EO, Banwo AI, et al. (2001) Nutritional rickets in young Nigerian children in the Sahel Savanna. East Afr Med J 78: 568-75.

5 Nield LS, Mahajan P, Joshi A, Kamat D (2006) Rickets: Not a disease of the Past. AFP 74: 619-26.

6Ovesen LC Brot, Jakobsen J (2003) Food contents and biological activity of 25-hydroxyvitamin D: a vitamin D metabolite to be reckoned with? Ann Nutr Metab 47:107-13.

7Mattila PH, Piironen VI, Uusi-Rauva EJ, Koivistoinen PE (1994) Vitamin D contents in edible mushrooms. J Agric Food Chem 42: 2449-53.

8Arnaud CD, Sanchez SD (1990) Calcium and Phosphorus. In: Present Knowledge in Nutrition. Washington, DC: International Life Science Institute, Nutritional Foundation. 212-23.

9Hameed A, Ahmad S, Rehman S, Urakzai AA, Gandapur AJ (1998) A study of nutritional rickets-morbidity and etiology of a ‘low profile’ disorder. J Post Med. Inst 12: 14-21.

10Khattak AA, Rehman G, Shah FU, Khan MK (2004) Study of Rickets in Admitted Patients at Lady Reading Hospital, Peshawar. Journal Post Medical Institute 18: 52-8.

11 Siddiqui TS, Rai MI (2005) Presentation and predisposing factors of nutritional rickets in children of Hazara Division. J Ayub Med Coll Abbottabad 17: 29-32.

12 Awan JA (2000) Calcium In: Elements of Food and Nutrition, Faisalabad. Pak 86.

13 Badruddin M, Thaver RIH (1997) Why rickets is still commonly seen in our children: lesson for Primary Care Physicians. Dow Medical College and civil Hospital, Karachi 21: 23-6.

14Bhattacharyya AK (1992) Nutritional rickets in tropics (review). World Review of Nutrition and Dietetics 67: 140.

15 Bouk GR, Siddiqui AI, Junejo B, Junejo AA, Abro HA (2009) Clinical presentation of nutritional rickets in children under 2 years of age. Med Channel 15: 55-58.

16Moorehead WR, Briggs HC (1974) 2-Amino-2-methyl-1-propanol as the alkalizing agent in an improved continuous-flow cresolphthalein complexone procedure for calcium in serum. Clin Chem 20: 1458-60.

17Pettifor JM (2005) Rickets and vitamin D deficiency in children and adolescents. Endocrinol and metabol clin of Nor Am 34: 537-53.

18 Pettifor JM (2008) Vitamin D &/or calcium deficiency rickets in infants & children: a global perspective. Indian J Med Res 127: 245-9.

19 Pugliese MT, Blumberg DL, Hludzinski J, Kay DS (1998) Nutritional Rickets in Suburbia. Journal of the American College of Nutrition 17: 637-41.

20Brown EM (2000) The extracellular Ca2+ - sensing receptor: central mediator of systemic calcium homeostasis. Annu Rev Nutr 20: 507-33.

21 Brunvand L, Quigstad E, Urdal P, Haug E (1996) Vitamin D deficiency and fetal growth. Early Hum Devel 45: 27-33.

22 Hartman JJ (2000) Vitamin D deficiency rickets in children: prevalence and need for community education. Orthopaedic Nursing 19: 63-7.

23Holick M (2004) Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr 80: 1678S-88S.

24Jamal A, Khanani AR, Biloo G, Asghar A, Jafri Z (1996) Rickets in a slum of Karachi. Pak J Med Sci 12: 247-50.

25 Joiner TA, Foster C, Shope T (2000) The many faces of vitamin D deficiency rickets. Pedicel Rew 21: 296-302.

26 Majeed R, Memon Y, Khowaja M, Majeed F, Ali MU, Rajar U (2007) Contributing factors of rickets among children at Hyderabad. JLUMHS 6: 60-65.

27 Michael F Holick (2004) Sunlight vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr 80: 1678S-88S.

28 Thomas L (1998) Clinical laboratory diagnostics, .Frankfurt: TH-Books.

29 Guder WG, Zawta B, et al (2001) The quality of diagnostic samples.1st ed. Darmstadt: GIT verlag 14-15.

30Molla AM, Badawi MH, Al-Yaish S, Sharma P, El-Salam RS, et al. (2000) Risk factors for nutritional rickets among children in Kuwait. Pediatric International 42: 280-4.

31Abdel Megeid FY, Al Abdul Karim BOI (2011) Genetic factor plays apart in the causationof vitamin D deficiency rickets at Riyadh. World J Med Sci 6: 74-82.

32 Raghuramulu N, V Reddy (1980) Serum 25-hydroxy-vitamin D levels in malnourished children with rickets. Archives of Disease in Childhood 55: 285-7.

33 Scientific Committee for Food (SCF) (1993) Nutrient and energy intakes for the European Community. Reports of the Scientific Committee for Food, Thirtyfirst Series. Luxembourg, European Commission.

34 Garabédian M, Ben-Mekhbi H (1999) Rickets and vitamin D deficiency. In: vitamin D physiology, molecular biology and clinical applications. M.F. Holick, editor. Humana Press, Totawa, NJ, USA, 273-86.

35Naheed T, Akbar N, Chaudhry A (2005) Bone mineral density measurement in a medical camp to identify osteopenic and osteoporotic subjects. Pak J Med Sci 21: 74-7.

36 Ozkan B, Doneray H, Karacan M, Vançelik S, Yýldýrým ZK, et al. (2009) Prevalence of vitamin D deficiency rickets in the eastern part of Turkey. Eur J Pedich 168: 95-100.

37Gordon CM, Feldman HA, Sinclair L (2008) Prevalence of vitamin D deficiency among healthy infants and toddlers. Arch Pediatr Adolesc Med 162: 505-12.

38 Ahmed IR, Ejaz MS, Mehnaz A, Shaikh FA (2011) Nutritional rickets: correlation between clinical, biochemical and radiological profile. Pak J Med Sci 27: 603-7.

39Shaw NJ, Kershaw M (2004) Vitamin D deficiency in children. In: David TJ editor(s). Recent Advances in Paediatrics 21. London: Royal Society of Medicine Press 85-100.

40Tezer H, Şıklar Z, Dallar Y, Doğankoç Ş (2009) Early and severe presentation of vitamin D deficiency and nutritional rickets among hospitalized infants and the effective factors. Turk J Pediatr 51: 110-5.

41 Fida NM (2003) Assessment of nutritional rickets in Western Saudi Arabia. Saudi Med J 24: 337-40.

42 Pettifor JM (2004) Nutritional rickets: deficiency of vitamin D, calcium, or both? A Journal of Clinical Nutrition 80: 1725S-1729S.

43Jan A, Ul-Haq I, Mustaan S (2011) Assessment of children with rickets at Khyber teaching hospital Peshawar. Gomal J Med Sci 9: 212-5.

44 Thacher TD, Fischer PR, Pettifor JM, Lawson JO, Isichei CO, Reading JC, Chan GM (1999) A Comparison of Calcium, Vitamin D, or Both for Nutritional Rickets in Nigerian Children. The New England Journal of Medicine 341: 563-8.

45Robinson PD, Hogler W, Craig ME, Verge CF, Walker JA, Piper AC, Woodhead HJ, Cowell CT, Ambler GR (2006) The re-emerging burden of Rickets: a decade of experience from Sydney. Arch Dis Child 91: 564-8.

46Usman J, Siddiqui H (2003) Osteoporosis in Family Practice. J Pak Med Assoc 53: 433-6.

47 Varley H (1958) Practical Clinical Bio-chemistry (2^nd Ed). Chapter XVI: 337-65.

48 Wagner CL, Greer FR (2008) Prevention of rickets and Vitamin D deficiency in infants, children, and adolescents: A clinical report of the American Academy of Pediatrics. Pediatrics 122: 1142-52.

49 Haider N, Ghaffar A, Khalid N, Khan MA (2010) Frequency of nutritional rickets in children admitted with severe pneumonia. J Pak Med Assoc 60: 729-32.

50 Younas M, Rahim F (2003) A cross-sectional study on epidemiology of rickets in Pakistani children. J Med Sci 11: 26-32.