Frank-Herrmann, P <br/><br/>
Natural family planning with and without barrier method use in the fertile phase: efficacy in relation to sexual behavior: a German prospective long-term study.  [electronic resource] 

 -  Advances in contraception : the official journal of the Society for the Advancement of Contraception   
 - 179-89 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0267-4874 
<br/><br/><label>Standard No.: </label>10.1023/a:1006551921219  doi 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Adult<br/>Contraceptive Devices<br/>Family Planning Services--methods<br/>Female<br/>Fertility<br/>Germany<br/>Humans<br/>Male<br/>Natural Family Planning Methods<br/>Ovulation Detection<br/>Pregnancy<br/>Prospective Studies<br/>Sexual Behavior<br/>Time Factors