Variations in general practitioners' response to postal questionnaires.
D001291:Attitude of Health Personnel; D003276:Contraceptives, Oral; D004522:Educational Status; D005193:Family Planning Services; D005194:Family Practice; D011177:Postal Service; D012067:Religion; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013997:Time Factors
D003276:Contraceptives, Oral