: ▁ 1 8 5 - 1 9 1 ▁Ber ger ud , ▁A . ▁T . ▁ 1 9 8 8 . ▁M ating ▁Systems ▁in ▁Gr ouse . ▁P ages ▁ 4 3 9 - 4 7 0 ▁in ▁Ada pt ive ▁strateg ies ▁and ▁population ▁e col ogy ▁of ▁northern ▁gr ouse . ▁( Ber ger ud , ▁A . ▁T . ▁and ▁M . ▁W . ▁Gr at son , ▁Ed s .) ▁Un iv . ▁of ▁Minnesota ▁Press , ▁Min ne apolis . ▁Ber ger ud , ▁A . ▁T . ▁and ▁M . ▁W . ▁Gr at son ▁ 1 9 8 8 . ▁Population ▁e col ogy ▁of ▁North ▁American ▁gr ouse . ▁P ages ▁ 5 7 8 - 6 8 5 ▁in ▁Ada pt ive ▁strateg ies ▁and ▁population ▁e col ogy ▁of ▁northern ▁gr ouse . ▁( Ber ger ud , ▁A . ▁T . ▁and ▁M . ▁W . ▁Gr at son , ▁Ed s .) ▁Un iv . ▁of ▁Minnesota ▁Press , ▁Min ne apolis ▁ ▁Clar ke , ▁Julia ▁A . ▁( 2 0 0 4 ): ▁Mor ph ology , ▁Ph y log en etic ▁Tax onomy , ▁and ▁System at ics ▁of ▁Ich thy orn is ▁and ▁Ap ator nis ▁( Av ial ae : ▁Or n ith ura e ). ▁Bul letin ▁of ▁the ▁American ▁Museum ▁of ▁Natural ▁History ▁ 2 8 6 : ▁ 1 - 1 7 9 ▁PDF ▁full text ▁Cla w son ,