...ecessary before a common ancestor is reached, but there are many different methods of computation. The fundamental relation in each of these steps is the {{Te

...es of the differences between the original and the graduated series. Other methods include {{TextTerm|moving averages|5|151|IndexEntry=moving average|OtherInd Methods of {{TextTerm|graphic representation|1|155|OtherIndexEntry=representation,

...|4|624}} from coitus, which are not usually considered to be contraceptive methods. A specific type of periodic abstinence ({{RefNumber|62|5|6}}) is classifie ...dexEntry=coitus interruptus}} or {{TextTerm|withdrawal|5|625|2}}. Another non-appliance method of contraception is {{TextTerm|periodic abstinence|6|625|OtherIndexE